标题： COVID-19对Twitter自我网络的影响：结构、情感和主题 显示英文标题

标题： The Impact of COVID-19 on Twitter Ego Networks: Structure, Sentiment, and Topics

摘要： 政府在新冠疫情初期实施的封锁措施减少了身体接触并限制了病毒传播，对面对面的社会互动施加了重大限制。 因此，个人转向在线社交平台以维持联系。 以人类管理有意义互动的认知限制为基础构建的自我网络（ego networks）为我们分析这些动态提供了一个框架。 身体接触的中断以及社会生活向线上转移可能改变了分配给管理这些数字关系的认知资源。 本研究旨在调查封锁措施对在线自我网络特征的影响，这可能是由于认知资源的重新分配所致。 为此，我们检查了一组大型推特用户数据集，涵盖了七年的活动时间。 分析一个包含五年疫情前和两年疫情期间的七年推特数据集，我们观察到明显但暂时的变化。 在封锁期间，自我网络扩大了，社交圈变得更加有组织，关系变得更加紧密。 同时，负面互动增加，用户参与更广泛的话题，表明主题多样性增加。 一旦限制解除，这些结构、情感和主题上的变化大多恢复到疫情前的常态——这表明对异常社会环境的一种暂时适应。 显示英文摘要

摘要： Lockdown measures, implemented by governments during the initial phases of the COVID-19 pandemic to reduce physical contact and limit viral spread, imposed significant restrictions on in-person social interactions. Consequently, individuals turned to online social platforms to maintain connections. Ego networks, which model the organization of personal relationships according to human cognitive constraints on managing meaningful interactions, provide a framework for analyzing such dynamics. The disruption of physical contact and the predominant shift of social life online potentially altered the allocation of cognitive resources dedicated to managing these digital relationships. This research aims to investigate the impact of lockdown measures on the characteristics of online ego networks, presumably resulting from this reallocation of cognitive resources. To this end, a large dataset of Twitter users was examined, covering a seven-year period of activity. Analyzing a seven-year Twitter dataset -- including five years pre-pandemic and two years post -- we observe clear, though temporary, changes. During lockdown, ego networks expanded, social circles became more structured, and relationships intensified. Simultaneously, negative interactions increased, and users engaged with a broader range of topics, indicating greater thematic diversity. Once restrictions were lifted, these structural, emotional, and thematic shifts largely reverted to pre-pandemic norms -- suggesting a temporary adaptation to an extraordinary social context.