Early detection of myocardial iron overload is crucial for optimal management of patients with beta thalassemia major, which could lead to intensification of iron chelating therapy. In this study, we evaluate the conventional echocardiography and tissue Doppler imaging measurements in patients with beta thalassemia major and further introduce the assessment of atrial ejection force as a feasible price-saving approach for early detection of myocardial iron overload. During a 1-year period, 42 cases of beta thalassemia major aged <21 years and with preserved systolic function were evaluated with magnetic resonance T2* imaging (MRI T2*), conventional echocardiography, and tissue Doppler imaging techniques. Patients were classified into two groups according to their myocardial MRI T2* values, with and without critical iron loading. All patients with echocardiographic evidence of moderate and severe stages of diastolic dysfunction showed critical iron loading in their MRI T2*. After excluding those patients with severe and moderate ventricular diastolic filling abnormality, the atrial ejection force index (P = 0.002) and a number of volume indexes of the left atrium showed a significant difference between the two groups. None of the tissue Doppler imaging measurements showed a statistically significant difference between the two groups. The atrial ejection force index of 7.41, with a sensitivity of 93% and a specificity of 74%, was suggested to detect critical cardiac iron loading. These results imply that combining the atrial ejection force index with the transmitral-derived echocardiographic assessment is a feasible way to detect early stages of myocardial iron overload in patients with beta thalassemia major.
Multiagent systems provide a basis for developing systems of autonomous entities and thus find application in a variety of domains. We consider a setting where not only the member agents are adaptive but also the multiagent system viewed as an entity in its own right is adaptive. Specifically, the social structure of a multiagent system can be reflected in the social norms among its members. It is well recognized that the norms that arise in society are not always beneficial to its members. We focus on prosocial norms, which help achieve positive outcomes for society and often provide guidance to agents to act in a manner that takes into account the welfare of others.
Specifically, we propose Cha, a framework for the emergence of prosocial norms. Unlike previous norm emergence approaches, Cha supports continual change to a system (agents may enter and leave) and dynamism (norms may change when the environment changes). Importantly, Cha agents incorporate prosocial decision making based on inequity aversion theory, reflecting an intuition of guilt arising from being antisocial. In this manner, Cha brings together two important themes in prosociality: decision making by individuals and fairness of system-level outcomes. We demonstrate via simulation that Cha can improve aggregate societal gains and fairness of outcomes.
After several decades of advances, simulation has become an important tool in the modeling of transportation systems and is widely applied in practice. Guides have been created by organizations in several countries, and dozens of papers have been published in scientific journals on the theory and application of transport simulation; these works are aimed at guiding practitioners in the use of simulation tools. However, transport simulation still lacks a unified and comprehensive guide for use in practice. The lack of such a document leads to conflicts between modelers, agencies, and decision makers and allows inappropriate use of the models. The outcome is often inaccurate results, inefficient use of resources, and conflict. This paper reviews and analyzes the existing transportation simulation guides. It identifies gaps and limitations and proposes an outline for a comprehensive simulation manual that is based on stakeholder input. Review of the existing guidance documents reveals that almost all these documents focus on traffic operations, and they provide either broad guidelines for building simulation models or advice on using a specific software product. Other issues, particularly those related to topics such as safety assessments, environmental impacts, public transportation, pedestrians, bicycles, simulation algorithms, agent-based simulation, and multimodal simulation, are addressed in only a cursory fashion. This paper proposes a possible structure for a transportation system simulation manual that would cover the limitations and gaps in the existing literature. The proposed document would consist of five volumes: concepts, model building, verification and validation, results analysis, and case studies and supplementary materials.
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