The School Sealant Program: An evaluation of the oral health education component

Dental caries is a common preventable childhood disease leading to severe physical, mental and economic repercussions for children and their families if left untreated. A needs assessment in Harris County reported that 45.9% of second graders had untreated dental caries. In order to address this growing problem, the School Sealant Program (SSP), a primary preventive initiative, was launched by the Houston Department of Health and Human Services (HDHHS) to provide oral health education, and underutilized dental preventive services to second grade children from participating Local School Districts (LSDs). ^ To determine the effectiveness and efficiency of the SSP, a program evaluation was conducted by the HDHHS between September 2007 and June 2008 for the Oral Health Education (OHE) component of the SSP. The objective of the evaluation was to assess short term changes in oral health knowledge of the participants and determine if these changes, if any, were due to the OHE sessions. An 8-item multiple choice pre/post test was developed for this purpose and administered to the participants before and immediately after the OHE sessions. ^ The present project analyzed pre and post test data of 1,088 second graders from 22 participating schools. Changes in overall and topic-specific knowledge of the program participants before and after the OHE sessions were analyzed using the Wilcoxon's signed rank test. ^ Results. The overall knowledge assessment showed a statistically significant (p <0.001) increase in the dental health knowledge of the participants after the oral health education sessions. Participants in the higher scoring category (7-8 correct responses) increased from 9.5% at baseline to 60.8% after the education sessions. Overall knowledge increased in all school regions with the highest knowledge gains seen in the Central and South regions. Males and females had similar knowledge gains. Significant knowledge differences were also found for each of the topic specific categories (functions of teeth, healthy diet, healthy habits, dental sealants; p<0.001) indicating an increase in topic specific knowledge of the participants post-health education sessions. ^ Conclusions. The OHE sessions were successful in increasing the short term oral health knowledge of the participants. ^

Sibling relationships in the family of a child with a burn injury

Purpose. Understanding siblings' experiences after a major childhood burn injury was the purpose of this mixed method, qualitative dominant study. The following research questions guided this project: How do siblings describe the impact of a major childhood burn injury experience? How do sibling relationship factors of warmth/closeness, relative status/power, conflict, and rivalry further clarify their relationship and their experience after a major burn injury? ^ Methods. A mixed method, qualitative dominant, design was implemented to understand the sibling experiences in a family with a child suffering from a major burn injury. Informants were selected from patients with childhood burn injuries attending the reconstructive clinic at a Gulf coast children's specialty hospital. The qualitative portion used the life story method, a narrative process, to portray the long-term impact on sibling relationships. A "case" represents a family unit and could be composed of one or multiple family members. Participants from 22 cases (N = 40 participants) were interviewed. Interviews were conducted in person and via telephone. The quantitative portion, or the embedded part of this mixed method design, used the Sibling Relationship Questionnaire Revised (SRQ-R) to conduct an additional structured interview and acquire scoring data. It was postulated that the SRQ-R would provide another perspective on the sibling experience and expand the qualitative data analysis. Thematic analysis was implemented on the qualitative interview data including the qualitative data from the interviews structured on the SRQ-R. Additionally, scores on the SRQ-R were tabulated to further describe the cases. ^ Results. The overall thematic pattern for the sibling relationship in families having a child with a major burn injury was that of normalization. Areas of normalization as well as the process of adjustment were the major themes. Areas of normalization were found in play and other activities, in school and work, and in family relations with their siblings and their parents. The process of adjustment in the sibling relationship was described as varied, involved school and work re-entry, and might even change their life perspective. Further analysis included an examination of the cases in which more than one person were interviewed and completed the SRQ-R. Participants from five ( n = 11) of six cases (n = 14), scored above 3.0 on the five-point scale on the Warmth/Closeness construct, indicating they perceived the sibling relationship as close. Five participants scored high on the Conflict construct and four participants scored high on the Rivalry construct. Finally, Relative Status/Power was low or negative in the six cases (n = 13). ^ Conclusions/implications. These findings suggest the importance of returning to normalcy for many of the families and the significance of sibling relationships on the process. Some of these families were able to use this major life event in a positive way to promote normalization. ^

Racial disparities in patient survival after liver transplantation in the United States

Background. Racial disparities in healthcare span such areas as access, outcomes after procedures, and patient satisfaction. Previous work suggested that minorities experience less healthcare and worse survival rates. In adult orthotopic liver transplantation (OLT) mixed results have been reported, with some showing African-American recipients having poor survival compared to Caucasians, and others finding no such discrepancy. ^ Purpose. This study’s purpose was to analyze the most recent United Network for Organ Sharing (UNOS) data, both before and after the implementation of the Model for End-Stage Liver Disease (MELD)/Pediatric End-Stage Liver Disease (PELD) scoring system, to determine if minority racial groups still experience poor outcomes after OLT. ^ Methods. The UNOS dataset for 1992-2001 (Era I) and 2002-2007 (Era II) was used. Patient survival rates for each Era and for adult and pediatric recipients were analyzed with adjustment. A separate multivariate analysis was performed on African-American adult patients in Era II in order to identify unique predictors for poor patient survival. ^ Results. The overall study included 66,118 OLT recipients. The majority were Caucasian (78%), followed by Hispanics (13%) and African-Americans (9%). Hispanic and African-American adults were more likely to be female, have Hepatitis C, to be in the intensive care unit (ICU) or ventilated at time of OLT, to have a MELD score ≥23, to have a lower education level, and to have public insurance when compared to Caucasian adults (all p-values < 0.05). Hispanic and African-American pediatric recipients were more likely have public insurance and less likely to receive a living donor OLT than were Caucasian pediatric OLT recipients (p <0.05). There was no difference in the likelihood of having a PELD score ≥21 among racial groups (p >0.40). African-American adults in Era I and Era II had worse patient survival rates than both Caucasians and Hispanic (pair-wise p-values <0.05). This same disparity was seen for pediatric recipients in Era I, but not in Era II. Multivariate analysis of African-American recipients revealed no unique predictors of patient death. ^ Conclusions. African-American race is still a predictor of poor outcome after adult OLT, even after adjustment for multiple clinical, demographic, and liver disease severity variables. Although African-American and Hispanic subgroups share many characteristics previously thought to increase risk of post-OLT death, only African-American patients have poor survival rates when compared to Caucasians. ^

Dietary patterns and risk of pancreatic cancer in a hospital-based case-control study

Background. It is important to understand the association between diet and risk of pancreatic cancer in order to better understand the etiology of pancreatic cancer.^ Objectives. Describe the dietary patterns of cases of adenocarcinoma of the pancreas and non-cancer controls and evaluate the odds of having a healthy eating pattern among cases and non-cancer controls.^ Design and Methods. An ongoing hospital-based case-control study was conducted in Houston, Texas from 2000-2008 with 678 pancreatic adenocarcinoma cases and 724 controls. Participants completed a food frequency questionnaire and a risk factor questionnaire. Dietary patterns were derived by principal component analysis and associations between dietary patterns and pancreatic cancer risk were assessed using unconditional logistic regression.^ Results. Two dietary patterns were derived: fruit-vegetable and high fat-meat. There were no statistically significant associations between the fruit-vegetable pattern and pancreatic cancer. An inverse association was seen between the high fat-meat pattern and pancreatic cancer risk when comparing those in the upper intake quintile to those scoring in the lowest quintile after adjusting for demographic and risk factor variables (OR=0.67, p=0.03). In sex-stratified analysis adjusted for demographic and risk factor variables, females scoring in the upper intake quintile of the fruit-vegetable pattern had a 49% lower risk of pancreatic cancer compared to females scoring in the lowest quintile (OR=0.51, p=0.03). An inverse relationship was also seen for the high fat-meat pattern when comparing females in the upper intake quintile to females in the lowest quintile (OR=0.50, p=0.03). In males, neither dietary pattern was significantly associated with pancreatic cancer.^ Conclusions. The current findings for the fruit-vegetable pattern are similar to those of previous studies and support the hypothesis that there is an inverse association between a “healthy” diet (comprised of fruits, vegetables, and whole grains) and risk of having pancreatic cancer (in females only). However, the inverse relationship with the high fat-meat pattern and risk of pancreatic cancer is contrary to other results. Further research on dietary patters and pancreatic cancer risk may lead to better understanding of the etiologic cause of pancreatic cancer.^

Nonpurging binge eaters versus nonbinge eaters and treatment retention for adult obesity

Dropout from obesity treatment has been a major factor associated with weight control failure, with few reliable predictors of dropouts or completers. Previous studies have tended to treat obese people as a homogeneous group with standard behavior modification-based interventions. Current research indicates there may be subgroups within the obese population, binge eaters and nonbinge eaters, who have different dropout rates. Current studies also recommend focusing on the subset of this subgroup that does not engage in purging (vomiting, laxative abuse, or excessive exercise) to compensate for binge eating. This research uses a secondary dataset (N = 156) from a prospective study in which participants were randomized to a Food Dependency (FD) and a Behavioral Self-Management (BSM) group for weight reduction. Criteria for subjects in the original study included (1) scoring higher on the existing Binge Eating Scale (BES) in order to ensure enrollment of more binge eaters and (2) no compensatory purging behavior for binge eating. Subjects were then reclassified in this study as binge eaters or nonbinge eaters using the more stringent proposed 1994 DSM-IV criteria for Binge Eating Disorder (BED). Subjects were followed for dropout. Variables studied were binge status, age at obesity onset, age at study baseline, class instructor, number of previous weight loss attempts, race, marital status, body mass index (BMI kg/m$\sp2$), type of intervention, work status, educational level, and social support. Stepwise backward regression Cox survival analysis indicated binge status had a consistent, statistically significant protective effect on dropout in which binge eaters were half as likely to dropout versus nonbinge eaters (p = 0.04). Cox proportional hazards analysis indicated no statistical difference in dropout by type of intervention (FD, p = 0.13; BSM, p = 0.80) when controlling for binge status. All other variables did not reach significance, which is consistent with the literature. Implications of these findings suggest that (1) the proposed 1994 DSM-IV criteria for BED is a more useful classification that the existing DSM-III-R criteria, and (2) the identification of subgroups among obese subjects is an important step in dropout and weight loss intervention research. Future research can confirm this finding. ^

The incidence of necrotizing changes in adults with pneumococcal pneumonia

Background. Necrotizing pneumonia is generally considered a rare complication of pneumococcal pneumonia in adults. We systematically studied the incidence of necrotizing changes in adult patients with pneumococcal pneumonia, and examined the severity of infection, the role of causative serotype and the association with bacteremia. ^ Methods. We used a data base of all pneumococcal infections identified at our medical center between 2000 and 2010. Original readings of chest X-rays (CXR) and computerized tomography (CT) were noted. All images were then reread independently by 2 radiologists. The severity of disease was assessed using the SMART-COP scoring system. ^ Results. There were 351 cases of pneumococcal pneumonia. Necrosis was reported in no original CXR readings and 6 of 136 (4.4%) CTs. With re-reading, 8 of 351 (2.3%) CXR and 15 of 136 (11.0%) CT had necrotizing changes. Overall, these changes were found in 23 of 351 (6.6%, 95% CI 4.0 - 9.1) patients. The incidence of bacteremia and the admitting SMART-COP scores were similar in patients with and without necrosis (P=1.00 and P=0.32, respectively). Type 3 pneumococcus was more commonly isolated from patients with than from patients without necrotizing pneumonia (P=0.05), but a total of 10 serotypes were identified among 16 cases in which the organism was available for typing. ^ Conclusions. Necrotizing changes in the lungs were seen in 6.6% (95% CI 4.0 - 9.1) of a large series of adults with pneumococcal pneumonia. Patients with necrosis were not more likely to have bacteremia or more severe disease. Type 3 pneumococcus was commonly implicated, but 9 other serotypes were also identified.^

Bayesian and survival model for tumor relapse status and disease-specific survival, with applications to breast cancer

Breast cancer is the most common non-skin cancer and the second leading cause of cancer-related death in women in the United States. Studies on ipsilateral breast tumor relapse (IBTR) status and disease-specific survival will help guide clinic treatment and predict patient prognosis.^ After breast conservation therapy, patients with breast cancer may experience breast tumor relapse. This relapse is classified into two distinct types: true local recurrence (TR) and new ipsilateral primary tumor (NP). However, the methods used to classify the relapse types are imperfect and are prone to misclassification. In addition, some observed survival data (e.g., time to relapse and time from relapse to death)are strongly correlated with relapse types. The first part of this dissertation presents a Bayesian approach to (1) modeling the potentially misclassified relapse status and the correlated survival information, (2) estimating the sensitivity and specificity of the diagnostic methods, and (3) quantify the covariate effects on event probabilities. A shared frailty was used to account for the within-subject correlation between survival times. The inference was conducted using a Bayesian framework via Markov Chain Monte Carlo simulation implemented in softwareWinBUGS. Simulation was used to validate the Bayesian method and assess its frequentist properties. The new model has two important innovations: (1) it utilizes the additional survival times correlated with the relapse status to improve the parameter estimation, and (2) it provides tools to address the correlation between the two diagnostic methods conditional to the true relapse types.^ Prediction of patients at highest risk for IBTR after local excision of ductal carcinoma in situ (DCIS) remains a clinical concern. The goals of the second part of this dissertation were to evaluate a published nomogram from Memorial Sloan-Kettering Cancer Center, to determine the risk of IBTR in patients with DCIS treated with local excision, and to determine whether there is a subset of patients at low risk of IBTR. Patients who had undergone local excision from 1990 through 2007 at MD Anderson Cancer Center with a final diagnosis of DCIS (n=794) were included in this part. Clinicopathologic factors and the performance of the Memorial Sloan-Kettering Cancer Center nomogram for prediction of IBTR were assessed for 734 patients with complete data. Nomogram for prediction of 5- and 10-year IBTR probabilities were found to demonstrate imperfect calibration and discrimination, with an area under the receiver operating characteristic curve of .63 and a concordance index of .63. In conclusion, predictive models for IBTR in DCIS patients treated with local excision are imperfect. Our current ability to accurately predict recurrence based on clinical parameters is limited.^ The American Joint Committee on Cancer (AJCC) staging of breast cancer is widely used to determine prognosis, yet survival within each AJCC stage shows wide variation and remains unpredictable. For the third part of this dissertation, biologic markers were hypothesized to be responsible for some of this variation, and the addition of biologic markers to current AJCC staging were examined for possibly provide improved prognostication. The initial cohort included patients treated with surgery as first intervention at MDACC from 1997 to 2006. Cox proportional hazards models were used to create prognostic scoring systems. AJCC pathologic staging parameters and biologic tumor markers were investigated to devise the scoring systems. Surveillance Epidemiology and End Results (SEER) data was used as the external cohort to validate the scoring systems. Binary indicators for pathologic stage (PS), estrogen receptor status (E), and tumor grade (G) were summed to create PS+EG scoring systems devised to predict 5-year patient outcomes. These scoring systems facilitated separation of the study population into more refined subgroups than the current AJCC staging system. The ability of the PS+EG score to stratify outcomes was confirmed in both internal and external validation cohorts. The current study proposes and validates a new staging system by incorporating tumor grade and ER status into current AJCC staging. We recommend that biologic markers be incorporating into revised versions of the AJCC staging system for patients receiving surgery as the first intervention.^ Chapter 1 focuses on developing a Bayesian method to solve misclassified relapse status and application to breast cancer data. Chapter 2 focuses on evaluation of a breast cancer nomogram for predicting risk of IBTR in patients with DCIS after local excision gives the statement of the problem in the clinical research. Chapter 3 focuses on validation of a novel staging system for disease-specific survival in patients with breast cancer treated with surgery as the first intervention. ^

Functional Analysis of Drosophila Integrator Complex in snRNA 3' End Processing

Uridine-rich small nuclear RNAs (U snRNAs) play essential roles in eukaryotic gene expression by facilitating the removal of introns from mRNA precursors and the processing of the replication-dependent histone pre-mRNAs. Formation of the 3’ end of these snRNAs is carried out by a poorly characterized, twelve-membered protein complex named Integrator Complex. In the effort to understand Integrator Complex function in the formation of the snRNA 3’ end, we performed a functional RNAi screen in Drosophila S2 cells to identify protein factors required for snRNA 3’ end formation. This screen was conducted by using a fluorescence-based reporter that elicits GFP expression in response to a deficiency in snRNA processing. Besides scoring the known Integrator subunits, we identified Asunder and CG4785 as additional core members of the Integrator Complex. Additionally, we also found a conserved requirement for Cyclin C and Cdk8 in both fly and human snRNA 3’ end processing. We have further demonstrated that the kinase activity of Cdk8 is critical for snRNA 3’ end processing and is likely to function independent of its well-documented function within the Mediator Cdk8 module. Taken together, this work functionally defines the Drosophila Integrator Complex and demonstrates a novel function for Cyclin C/Cdk8 in snRNA 3’ end formation. This thesis work has also characterized an important functional interaction mediated by a microdomain within Integrator subunit 12 (IntS12) and IntS1 that is required for the activity of the Integrator Complex in processing the snRNA 3’ end. Through the development of a reporter-based functional RNAi-rescue assay in Drosophila S2 cells, we analyzed domains within IntS12 required for snRNA 3’ end formation. This analysis unexpectedly revealed that an N-terminal 30 amino acid region and not the highly conserved central PHD finger domain, is required for snRNA 3’ end cleavage. The IntS12 microdomain (1-45) functions autonomously, and is sufficient to interact and stabilize the putative scaffold protein IntS1. Our findings provide more details of the Integrator Complex for understanding the molecular mechanism of snRNA 3’ end processing. Moreover, these results lay the foundation for future studies of the complex through the identification of a novel functional domain within one subunit and the identification of additional subunits.

Baseline evaluation of environmental physical activity and nutrition support of Texas Medical Center hospital worksites

Background: Obesity is a major health problem in the United States that has reached epidemic proportions. With most U.S adults spending the majority of their waking hours at work, the influence of the workplace environment on obesity is gaining in importance. Recent research implicates worksites as providing an 'obesogenic' environment as they encourage overeating and reduce the opportunity for physical activity. Objective: The aim of this study is to describe the nutrition and physical activity environment of Texas Medical Center (TMC) hospitals participating in the Shape Up Houston evaluation study to develop a scoring system to quantify the environmental data collected using the Environmental Assessment Tool (EAT) survey and to assess the inter-observer reliability of using the EAT survey. Methods: A survey instrument that was adapted from the Environmental Assessment Tool (EAT) developed by Dejoy DM et al in 2008 to measure the hospital environmental support for nutrition and physical activity was used for this study. The inter-observer reliability of using the EAT survey was measured and total percent agreement scores were computed. Most responses on the EAT survey are dichotomous (Yes and No) and these responses were coded with a '0' for a 'no' response and a '1' for a 'yes' response. A summative scoring system was developed to quantify these responses. Each hospital was given a score for each scale and subscale on the EAT survey in addition to a total score. All analyses were conducted using Stata 11 software. Results: High inter-observer reliability is observed using EAT. The percentage agreement scores ranged from 94.4%–100%. Only 2 of the 5 hospitals had a fitness facility onsite and scores for exercise programs and outdoor facilities available for hospital employees ranged from 0–62% and 0–37.5%, respectively. The healthy eating percentage for hospital cafeterias range from 42%–92% across the different hospitals while the healthy vending scores were 0%–40%. The total TMC 'healthy hospital' score was 49%. Conclusion: The EAT survey is a reliable instrument for measuring the physical activity and nutrition support environment of hospital worksites. The study results showed a large variability among the TMC hospitals in the existing physical activity and nutrition support environment. This study proposes cost effective policy changes that can increase environmental support to healthy eating and active living among TMC hospital employees.^

Development and evaluation of a video-based modeling strategy for the dissemination phase of a school health tobacco -use prevention program

Even the best school health education programs will be unsuccessful if they are not disseminated effectively in a manner that encourages classroom adoption and implementation. This study involved two components: (1) the development of a videotape intervention to be used in the dissemination phase of a 4-year, NCI-funded diffusion study and (2) the evaluation of that videotape intervention strategy in comparison with a print (information transfer) strategy. Conceptualization has been guided by Social Learning Theory, Diffusion Theory, and communication theory. Additionally, the PRECEDE Framework has been used. Seventh and 8th grade classroom teachers from Spring Branch Independent School District in west Houston participated in the evaluation of the videotape and print interventions using a 57-item preadoption survey instrument developed by the UT Center for Health Promotion Research and Development. Two-way ANOVA was used to study individual score differences for five outcome variables: Total Scale Score (comprised of 57 predisposing, enabling, and reinforcing items), Adoption Characteristics Subscale, Attitude Toward Innovation Subscale, Receptivity Toward Innovation, and Reinforcement Subscale. The aim of the study is to compare the effect upon score differences of video and print interventions alone and in combination. Seventy-three 7th and 8th grade classroom teachers completed the study providing baseline and post-intervention measures on factors related to the adoption and implementation of tobacco-use prevention programs. Two-way ANOVA, in relation to the study questions, found significant scoring differences for those exposed to the videotape intervention alone for both the Attitude Toward Innovation Subscale and the Receptivity to Adopt Subscale. No significant results were found to suggest that print alone influences favorable scoring differences between baseline and post-intervention testing. One interaction effect was found suggesting video and print combined are more effective for influencing favorable scoring differences for the Reinforcement for the Adoption Subscale.^ This research is unique in that it represents a newly emerging field in health promotion communications research with implications for Social Learning Theory, Diffusion Theory, and communication science that are applicable to the development of improved school health interventions. ^

(Table 1) Dissolved organic carbon, water temperature and conductivity in three subarctic ponds near Kilpisjärvi, North Finland

Daphnia was collected from five subarctic ponds which differed greatly in their DOC contents and, consequently, their underwater light (UV) climates. Irrespective of which Daphnia species was present, and contrary to expectations, the ponds with the lowest DOC concentrations (highest UV radiation levels) contained Daphnia with the highest eicosapentaenoic acid (EPA) concentrations. In addition, EPA concentrations in these Daphnia generally decreased in concert with seasonally increasing DOC concentrations. Daphnia from three of the ponds was also tested for its tolerance to solar ultraviolet radiation (UVR) with respect to survival. Daphnia pulex from the clear water pond showed, by far, the best UV-tolerance, followed by D. longispina from the moderately humic and D. longispina from the very humic pond. In addition, we measured sublethal parameters related to UV-damage such as the degree to which the gut of Daphnia appeared green (as a measure of their ability to digest algae), and whether their guts appeared damaged. We developed a simple, noninvasive scoring system to quantify the proportion of the gut in which digestive processes were presumably active. This method allowed repeated measurement of the same animals over the course of the experiment. We demonstrated, for the first time, that sublethal damage of the gut precedes mortality caused by exposure to UVR. In a parallel set of experiments we fed UV-exposed and non-exposed algae to UV-exposed and non-exposed daphnids. UVR pretreatment of algae enhanced the negative effects of exposure to natural solar UV-irradiation in Daphnia. These UV-related effects were generally not specific to the species of Daphnia.

Théorie des jeux expérimentale & action motrice

How do sportspeople succeed in a non-collaborative game? An illustration of a perverse side effect of altruism Are team sports specialists predisposed to collaboration? The scientific literature on this topic is divided. The present article attempts to end this debate by applying experimental game theory. We constituted three groups of volunteers (all students aged around 20): 25 team sports specialists; 23 individual sports specialists (gymnasts, track & field athletes and swimmers) and a control group of 24 non-sportspeople. Each subgroup was divided into 3 teams that played against each other in turn (and not against teams from other subgroups). The teams played a game based on the well-known Prisoner's Dilemma (Tucker, 1950) - the paradoxical "Bluegill Sunbass Game" (Binmore, 1999) with three Nash equilibria (two suboptimal equilibria with a pure strategy and an optimal equilibrium with a mixed, egotistical strategy (p= 1/2)). This game also features a Harsanyi equilibrium (based on constant compliance with a moral code and altruism by empathy: "do not unto others that which you would not have them do unto you"). How, then, was the game played? Two teams of 8 competed on a handball court. Each team wore a distinctive jersey. The game lasted 15 minutes and the players were allowed to touch the handball ball with their feet or hands. After each goal, each team had to return to its own half of the court. Players were allowed to score in either goal and thus cooperate with their teammates or not, as they saw fit. A goal against the nominally opposing team (a "guardian" strategy, by analogy with the Bluegill Sunbass Game) earned a point for everyone in the team. For an own goal (a "sneaker" strategy), only the scorer earned a point - hence the paradox. If all the members of a team work together to score a goal, everyone is happy (the Harsanyi solution). However, the situation was not balanced in the Nashian sense: each player had a reason to be disloyal to his/her team at the merest opportunity. But if everyone adopts a "sneaker" strategy, the game becomes a free-for-all and the chances of scoring become much slimmer. In a context in which doubt reigns as to the honesty of team members and "legal betrayals", what type of sportsperson will score the most goals? By analogy with the Bluegill Sunbass Game, we recorded direct motor interactions (passes and shots) based on either a "guardian" tactic (i.e. collaboration within the team) or a "sneaker" tactic (shots and passes against the player's designated team). So, was the group of team sports specialist more collaborative than the other two groups? The answer was no. A statistical analysis (difference from chance in a logistic regression) enabled us to draw three conclusions: ?For the team sports specialists, the Nash equilibrium (1950) was stronger than the Harsanyi equilibrium (1977). ?The sporting principles of equilibrium and exclusivity are not appropriate in the Bluegill Sunbass Game and are quickly abandoned by the team sports specialists. The latter are opportunists who focus solely on winning and do well out of it. ?The most altruistic players are the main losers in the Bluegill Sunbass Game: they keep the game alive but contribute to their own defeat. In our experiment, the most altruistic players tended to be the females and the individual sports specialists

Théorie des jeux expérimentale & action motrice

How do sportspeople succeed in a non-collaborative game? An illustration of a perverse side effect of altruism Are team sports specialists predisposed to collaboration? The scientific literature on this topic is divided. The present article attempts to end this debate by applying experimental game theory. We constituted three groups of volunteers (all students aged around 20): 25 team sports specialists; 23 individual sports specialists (gymnasts, track & field athletes and swimmers) and a control group of 24 non-sportspeople. Each subgroup was divided into 3 teams that played against each other in turn (and not against teams from other subgroups). The teams played a game based on the well-known Prisoner's Dilemma (Tucker, 1950) - the paradoxical "Bluegill Sunbass Game" (Binmore, 1999) with three Nash equilibria (two suboptimal equilibria with a pure strategy and an optimal equilibrium with a mixed, egotistical strategy (p= 1/2)). This game also features a Harsanyi equilibrium (based on constant compliance with a moral code and altruism by empathy: "do not unto others that which you would not have them do unto you"). How, then, was the game played? Two teams of 8 competed on a handball court. Each team wore a distinctive jersey. The game lasted 15 minutes and the players were allowed to touch the handball ball with their feet or hands. After each goal, each team had to return to its own half of the court. Players were allowed to score in either goal and thus cooperate with their teammates or not, as they saw fit. A goal against the nominally opposing team (a "guardian" strategy, by analogy with the Bluegill Sunbass Game) earned a point for everyone in the team. For an own goal (a "sneaker" strategy), only the scorer earned a point - hence the paradox. If all the members of a team work together to score a goal, everyone is happy (the Harsanyi solution). However, the situation was not balanced in the Nashian sense: each player had a reason to be disloyal to his/her team at the merest opportunity. But if everyone adopts a "sneaker" strategy, the game becomes a free-for-all and the chances of scoring become much slimmer. In a context in which doubt reigns as to the honesty of team members and "legal betrayals", what type of sportsperson will score the most goals? By analogy with the Bluegill Sunbass Game, we recorded direct motor interactions (passes and shots) based on either a "guardian" tactic (i.e. collaboration within the team) or a "sneaker" tactic (shots and passes against the player's designated team). So, was the group of team sports specialist more collaborative than the other two groups? The answer was no. A statistical analysis (difference from chance in a logistic regression) enabled us to draw three conclusions: ?For the team sports specialists, the Nash equilibrium (1950) was stronger than the Harsanyi equilibrium (1977). ?The sporting principles of equilibrium and exclusivity are not appropriate in the Bluegill Sunbass Game and are quickly abandoned by the team sports specialists. The latter are opportunists who focus solely on winning and do well out of it. ?The most altruistic players are the main losers in the Bluegill Sunbass Game: they keep the game alive but contribute to their own defeat. In our experiment, the most altruistic players tended to be the females and the individual sports specialists

Théorie des jeux expérimentale & action motrice

How do sportspeople succeed in a non-collaborative game? An illustration of a perverse side effect of altruism Are team sports specialists predisposed to collaboration? The scientific literature on this topic is divided. The present article attempts to end this debate by applying experimental game theory. We constituted three groups of volunteers (all students aged around 20): 25 team sports specialists; 23 individual sports specialists (gymnasts, track & field athletes and swimmers) and a control group of 24 non-sportspeople. Each subgroup was divided into 3 teams that played against each other in turn (and not against teams from other subgroups). The teams played a game based on the well-known Prisoner's Dilemma (Tucker, 1950) - the paradoxical "Bluegill Sunbass Game" (Binmore, 1999) with three Nash equilibria (two suboptimal equilibria with a pure strategy and an optimal equilibrium with a mixed, egotistical strategy (p= 1/2)). This game also features a Harsanyi equilibrium (based on constant compliance with a moral code and altruism by empathy: "do not unto others that which you would not have them do unto you"). How, then, was the game played? Two teams of 8 competed on a handball court. Each team wore a distinctive jersey. The game lasted 15 minutes and the players were allowed to touch the handball ball with their feet or hands. After each goal, each team had to return to its own half of the court. Players were allowed to score in either goal and thus cooperate with their teammates or not, as they saw fit. A goal against the nominally opposing team (a "guardian" strategy, by analogy with the Bluegill Sunbass Game) earned a point for everyone in the team. For an own goal (a "sneaker" strategy), only the scorer earned a point - hence the paradox. If all the members of a team work together to score a goal, everyone is happy (the Harsanyi solution). However, the situation was not balanced in the Nashian sense: each player had a reason to be disloyal to his/her team at the merest opportunity. But if everyone adopts a "sneaker" strategy, the game becomes a free-for-all and the chances of scoring become much slimmer. In a context in which doubt reigns as to the honesty of team members and "legal betrayals", what type of sportsperson will score the most goals? By analogy with the Bluegill Sunbass Game, we recorded direct motor interactions (passes and shots) based on either a "guardian" tactic (i.e. collaboration within the team) or a "sneaker" tactic (shots and passes against the player's designated team). So, was the group of team sports specialist more collaborative than the other two groups? The answer was no. A statistical analysis (difference from chance in a logistic regression) enabled us to draw three conclusions: ?For the team sports specialists, the Nash equilibrium (1950) was stronger than the Harsanyi equilibrium (1977). ?The sporting principles of equilibrium and exclusivity are not appropriate in the Bluegill Sunbass Game and are quickly abandoned by the team sports specialists. The latter are opportunists who focus solely on winning and do well out of it. ?The most altruistic players are the main losers in the Bluegill Sunbass Game: they keep the game alive but contribute to their own defeat. In our experiment, the most altruistic players tended to be the females and the individual sports specialists