From an evolutionary perspective, art presents many puzzles. Humans invest substantial effort in generating apparently useless displays that include artworks. These vary greatly from ordinary to intricate. From the perspective of signalling theory, these investments in highly complex artistic designs can reflect information about individuals and their social standing. Using a large corpus of kolam art from South India (N = 3139 kolam from 192 women), we test a number of hypotheses about the ways in which social stratification and individual differences affect the complexity of artistic designs. Consistent with evolutionary signalling theories of constrained optimisation, we find that kolam art tends to occupy a \'sweet spot\' at which artistic complexity, as measured by Shannon information entropy, remains relatively constant from small to large drawings. This stability is maintained through an observable, apparently unconscious trade-off between two standard information-theoretic measures: richness and evenness. Although these drawings arise in a highly stratified, caste-based society, we do not find strong evidence that artistic complexity is influenced by the caste boundaries of Indian society. Rather, the trade-off is likely due to individual-level aesthetic preferences and differences in skill, dedication and time, as well as the fundamental constraints of human cognition and memory.

Financial burden due to poor occupational safety practices remains high although occupational health and safety (OHS) have improved in recent years. Conducting risk assessment is one way to improve OHS. Workplaces may not have sufficient expertise in risk assessment. The aim of this study was to identify the needed OHS risk assessment skills, current support in the workplaces and the ways to improve risk assessment skills. This study was conducted with the Delphi survey for OHS experts (n = 13) and with interviews (n = 41) in the case companies. OHS experts agreed that the most significant skills were for employees to identify hazards and minimize risks in one\'s work; for supervisors to influence others with a good example; and for OHS experts to understand and manage the wholeness of safety practices and understand and manage the meaning, concepts, and criteria of risk assessment. The current main support methods were learning at work, training and written instructions. However, many of the interviewees felt that they had not received risk assessment training and that the support depended on their activity. Finally, the OHS experts determined that the most feasible ways to improve risk assessment skills were training, coaching and giving clear instructions. Likewise, the interviewees suggested various training methods. Based on these results, concrete development plans to improve risk assessment skills can be made.

OBJECTIVE: To assess the effect of operative technique on staple line leaks after laparoscopic sleeve gastrectomy (LSG).
BACKGROUND: Staple-line leaks after LSG are a major source of morbidity and mortality. Variations in operative technique exist; however, their effect on leaks is poorly understood.
METHODS: We analyzed data from the Michigan Bariatric Surgery Collaborative (MBSC) to perform a case-control study comparing patients who had a clinically significant leak after undergoing a primary LSG to those who did not. A total of 45 patients with leaks were identified between January 2007 and December 2013. The leak group was matched 1:2 to a control group based on procedure type, age, body mass index, sex, and year the procedure was performed. Technique-specific factors were assessed by reviewing operative notes from all primary bariatric procedures in our study population. Conditional logistic regression was used to identify techniques associated with leaks. To increase the power of our analysis, we used a significance level of .10.
RESULTS: Leak rates with LSG have decreased over the past 5 years (1.18% to .36%) as annual case volume has increased (846 cases/yr to 4435 cases/yr). Surgeons who performed 43 or more cases per year had a leak rate<1%. Leaks were more common among cases requiring a blood transfusion (26.2% versus 1.08%, P = .0031) and when cases were converted to open surgery (7.14% versus 0%, P = .0741). However, there was no significant difference in operative time between cases involving a leak and their matched controls (95.4 min versus 87.1 min, P = .1197). Oversewing of the staple line was the only technique associated with less leaks after controlling for confounding factors (OR .397 CI .174, .909, P = .0665). Notably, surgeons who oversewed routinely were also found to have higher case volume (307 versus 140, P = .0216) and less overall complication rates (4.81% versus 7.95%, P = .0027). Furthermore, oversewing technique varied widely as only 22.6% of cases involved oversewing of the entire staple line.
CONCLUSIONS: Despite considerable variation in operative technique, leak rates with laparoscopic sleeve gastrectomy have decreased over time as operative volume has increased. Oversewing of the staple line was associated with fewer leaks, but specific suturing technique was not uniform and oversewing was performed routinely by more experienced surgeons with higher case volumes and less complication rates overall. Before standardizing surgical technique one must take into account variations in surgeon skill and experience.

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