A review of some of the 35 + studies applying Kauffman's NK model to an administrative context unquestioningly presume that groupthink predominates—a misrepresentation of reality in many firms. Groupthink results from strong ties (contacts); novelty and entrepreneurship results from weak ties. The biological basis of the NK model leads to groupthink. But employees don't usually behave like genes. Recent findings in the strong-tie/weak-tie literature are presented, leading up to the notion of a tipping point. But, how many weak-ties does a firm need before its overall behavior tips from groupthink to innovation? The NK model is changed in just one way so that it produces results showing the transition from strong- to weak-tie situations. The one change introduces F, the number of contacts per year; it varies from once a week to once a year. How “weak” do ties have to become before novelty effects result? Our results clearly show that the “F” variable negates the standard NK effect of emergent “complexity catastrophe,” which is a dramatic loss of overall fitness. And, yes, there is a tipping point.

Background Previous studies showed the adverse impacts of air pollution on headache attacks in developed countries. However, evidence is limited to the impact of exposure to air pollutants on headache attacks. In this study, we aimed to explore the impact of nitrogen dioxide (NO2) exposure on neurology clinic visits (NCVs) for headache onsets. Methods Records of NCVs for headaches, concentrations of ambient NO2, and meteorological variables were collected in Wuhan, China, from January 1st, 2017, to November 30th, 2019. A time-series study was conducted to investigate the short-term effects of NO2 exposure on daily NCVs for headaches. Stratified analyses were also computed according to season, age, and sex, and the exposure–response (E-R) curve was then plotted. Results A total of 11,436 records of NCVs for headaches were enrolled in our study during the period. A 10-μg/m3 increase of ambient NO2 corresponded to a 3.64% elevation of daily NCVs for headaches (95%CI: 1.02%, 6.32%, P = 0.006). Moreover, females aged less than 50 years of age were more susceptible compared to males (4.10% vs. 2.97%, P = 0.007). The short-term effects of NO2 exposure on daily NCVs for headaches were stronger in cool seasons than in warm seasons (6.31% vs. 0.79%, P = 0.0009). Conclusion Our findings highlight that short-term exposure to ambient NO2 positively correlated with NCVs for headaches in Wuhan, China, and the adverse effects varied by season, age, and sex.

Mahalanobis-Taguchi System (MTS), as a pattern recognition method by constructing a continuous measurement scale, has a very good performance on classification and feature selection for real-valued data. However, the record of symbolic interval data has become a common practice with the recent advances in database technologies. Kernel methods not only are powerful statistical nonlinear learning methods, but also can be defined over objects as diverse as graphs, sets, strings, and text documents. In this paper, we derive kernel Mahalanobis distance (KMD) to extend MTS to symbolic interval data. To evaluate the proposed method, four experiments with synthetic symbolic interval data sets and seven experiments with real symbolic interval data sets are performed and we have compared our method with MTS based on interval Mahalanobis distance (IMD). The experimental results show our method has a better classification performance than MTS based on IMD on Accuracy, Specificity, Sensitivity, and G-means. However, MTS based on IMD has a stronger dimension reduction rate than our method.

BackgroundPrevious studies have explored the correlation between short-term exposure to air pollution and urinary system diseases, but lack of evidence on the correlation between air pollution and urolithiasis.MethodsDaily data of emergency department visits (EDVs), concentrations of six air pollutants (SO2, NO2, PM2.5, PM10, CO, and O3) and meteorological variables were collected in Wuhan, China, from 2016 to 2018. And a time-series study was conducted to investigate short-term effects of air pollutants on urolithiasis EDVs. In addition, stratified analyses by season, age and gender were also conducted.ResultsA total of 7,483 urolithiasis EDVs were included during the study period. A 10-μg/m3 increase of SO2, NO2, PM2.5, CO, PM10, and O3 corresponded to 15.02% (95% confidence interval [CI]: 1.69%, 30.11%), 1.96% (95% CI: 0.19%, 3.76%), 1.09% (95% CI:−0.24%, 2.43%), 0.14% (95% CI: 0.02%, 0.26%), 0.72% (95% CI: 0.02%, 1.43%), and 1.17% (95% CI: 0.40%, 1.94%) increases in daily urolithiasis EDVs. Significant positive correlations were observed between SO2, NO2, CO, and O3 and urolithiasis EDVs. The correlations were mainly among females (especially PM2.5 and CO) and younger people (especially SO2, NO2, and PM10) but the effect of CO was more obvious in elders. Furthermore, the effects of SO2 and CO were stronger in warm seasons, while the effects of NO2 were stronger in cool seasons.ConclusionOur time-series study indicates that short-term exposure to air pollution (especially SO2, NO2, CO, and O3) was positively correlated with EDVs for urolithiasis in Wuhan, China, and the effects varied by season, age and gender.