640 research outputs found

    Fullerenes with the maximum Clar number

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    The Clar number of a fullerene is the maximum number of independent resonant hexagons in the fullerene. It is known that the Clar number of a fullerene with n vertices is bounded above by [n/6]-2. We find that there are no fullerenes whose order n is congruent to 2 modulo 6 attaining this bound. In other words, the Clar number for a fullerene whose order n is congruent to 2 modulo 6 is bounded above by [n/6]-3. Moreover, we show that two experimentally produced fullerenes C80:1 (D5d) and C80:2 (D2) attain this bound. Finally, we present a graph-theoretical characterization for fullerenes, whose order n is congruent to 2 (respectively, 4) modulo 6, achieving the maximum Clar number [n/6]-3 (respectively, [n/6]-2)

    Predictors of father involvement : the role of early life events and stressors.

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    This study utilized the National Longitudinal Survey of Youth 1997 (NLSY97) dataset to examine the effect of men’s early life stressful events and their father involvement with their new biological child(ren). The problems associated with low level of father involvement or even father absence in the country followed by the dearth of studying men who experienced stressful events during childhood were first discussed. A series of factors in the literature that can affect the level of father involvement and various of childhood stressful events were also presented. Following this, the characteristics of study subjects’ demographics, household information, men’s crime history, substance use history, early life stressful events, and men’s father/figure were studied. A logistic regression analysis was used to determine the best predictors of the level of men’s involvement with their new biological child(ren). The best predictors were age when a man became a father and whether he had been arrested in childhood. Future research is needed to evaluate fathering activities representative of the direct and indirect engagement dimensions

    Internet-based Distributed Collaborative Engineering Analysis

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    This paper proposes an engineering analysis environment that allows remote users to conduct three-dimensional finite element analysis collaboratively through the Internet. Java and Java 3D were chosen to develop the working prototype due to their advantages of platform-independence and network supporting. The environment allows remote users to work collaboratively on the same analysis object simultaneously. It reads the geometric data generated by the collaborative geometric modeling environment. The user can interact directly with the geometric model to perform operations, such as applying, editing, and deleting boundary conditions and forces. The operations are propagated among the team members, which creates a distributed shared environment. The commands are transmitted instead of the generated data, and thus the network traffic associated with the collaboration is minimized. Different from classical server/client models,# the environment adopts a strategy in which the client-side application has full analysis capabilities while the server only manages communication. The essential features for distributed collaboration are discussed. The actual design consideration of the working prototype is presented to help illustrate the complexity and development of the collaborative environment. The environment is open to the public at www.vcity.ou.edu.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Prognosis Prediction of Stroke based on Machine Learning and Explanation Model

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    The prognosis prediction of stroke is of great significance to its prevention and treatment. This paper used machine learning to predict stroke prognosis, and use SHAP method to make feature importance and single sample analysis. Firstly, feature engineering, use Borderline-SMOTE algorithm to deal with data imbalance, use Support Vector Machine(SVM) to build a prognostic prediction model, and use Random Forest(RF), Decision Tree(DT), Logistic Regression(LR) for comparative analysis, and find the performance of SVM after feature engineering better than other models, the accuracy, specificity, F1 score, AUC value reach 0.8306, 0.8356, 0.8415 and 0.9140. Then, the model was further analyzed for explainability, and it was found that the top three causes of the disease were Glasgow Coma Score, NIHSS and atrial fibrillation. Finally, try to analysis a single sample, which is performed to determine that the patient is a low-risk patient, and suffering from atrial fibrillation is the largest potential risk factor for the patient
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