SC-block: Supervised contrastive blocking within entity resolution pipelines

Millions of websites use the schema.org vocabulary to annotate structured data describing products, local businesses, or events within their HTML pages. Integrating schema.org data from the Semantic Web poses distinct requirements to entity resolution methods: (1) the methods must scale to millions of entity descriptions and (2) the methods must be able to deal with the heterogeneity that results from a large number of data sources. In order to scale to numerous entity descriptions, entity resolution methods combine a blocker for candidate pair selection and a matcher for the fine-grained comparison of the pairs in the candidate set. This paper introduces SC-Block, a blocking method that uses supervised contrastive learning to cluster entity descriptions in an embedding space. The embedding enables SC-Block to generate small candidate sets even for use cases that involve a large number of unique tokens within entity descriptions. To measure the effectiveness of blocking methods for Semantic Web use cases, we present a new benchmark, WDC-Block. WDC-Block requires blocking product offers from 3,259 e-shops that use the schema.org vocabulary. The benchmark has a maximum Cartesian product of 200 billion pairs of offers and a vocabulary size of 7 million unique tokens. Our experiments using WDC-Block and other blocking benchmarks demonstrate that SC-Block produces candidate sets that are on average 50% smaller than the candidate sets generated by competing blocking methods. Entity resolution pipelines that combine SC-Block with state-of-the-art matchers finish 1.5 to 4 times faster than pipelines using other blockers, without any loss in F1 score

Ethnic friendship segregation in the school class – The role of homophily preferences of gender, socioeconomic status, and religion in four European countries

This dissertation explores social integration by studying the evolution of friendships between young migrants and natives in school classes across Germany, the Netherlands, the United Kingdom, and Sweden, utilizing data from the Children of Immigrants Longitudinal Survey in Four European Countries (CILS4EU). It aims to identify the social factors influencing the formation of inter-ethnic and inter-religious friendships, focusing on the boundaries between ethnic groups within school environments. The first study emphasizes the significance of opportunity structure in friendship formation between natives and migrants. Employing ego-level (pooled OLS) and dyad-level (2-step approach on firthlogit and multilevel logit) techniques, it demonstrates that gender availability within ethnic groups plays a crucial role in inter-ethnic friendship formation. Specifically, lower gender availability within one's own ethnic group correlates with an increased probability of cross-group friendships. This highlights the dominance of gender over ethnicity in shaping social segregation among youth in educational environments, underscoring a broader pattern: the pivotal role of opportunity structure “within” social categories. In the second study, grounded in exchange theory, the research explores the role of social exchange in intergroup friendships between native and migrant adolescents. Utilizing ego-level (OLS) and dyad-level (multi-level logit) analyses, the study investigates the interplay between parental socioeconomic status (SES) and immigrant status in friendship formation. While rising relative SES among migrants fosters greater inter-group friendships, the analysis also reveals a nuanced mixture of status exchange and status similarity preferences, with the latter exerting a stronger influence. These findings underscore the significance of examining the interplay between status exchange and status similarity preferences in shaping the formation of inter-ethnic friendships among adolescents. The third study examines the integration of Muslim migrants in Western societies, with a focus on how attitudes toward sexual liberalization influence friendship dynamics within school environments. By employing multilevel exponential random graph models (MLERGMs), the study reveals that attitudes toward sexual liberalization play a mediating role in Muslim segregation. Specifically, when controlling for attitude homophily, the study reveals a reduction in the tendency of Muslim migrants to form friendships within their religious denomination. However, despite this mediation effect, a significant portion of religious segregation remains unexplained, emphasizing the need for future research to delve deeper into the underlying factors shaping Muslim friendship segregation

Establishing an MSU service in a medium-sized German urban area — clinical and economic considerations

Background and purpose: Mobile stroke units (MSU) have been demonstrated to improve prehospital stroke care in metropolitan and rural regions. Due to geographical, social and structural idiosyncrasies of the German city of Mannheim, concepts of established MSU services are not directly applicable to the Mannheim initiative. The aim of the present analysis was to identify major determinants that need to be considered when initially setting up a local MSU service. Methods: Local stroke statistics from 2015 to 2021 were analyzed and circadian distribution of strokes and local incidence rates were calculated. MSU patient numbers and total program costs were estimated for varying operating modes, daytime coverage models, staffing configurations which included several resource sharing models with the hospital. Additional case-number simulations for expanded catchment areas were performed. Results: Median time of symptom onset of ischemic stroke patients was 1:00 p.m. 54.3% of all stroke patients were admitted during a 10-h time window on weekdays. Assuming that MSU is able to reach 53% of stroke patients, the average expected number of ischemic stroke patients admitted to MSU would be 0.64 in a 10-h shift each day, which could potentially be increased by expanding the MSU catchment area. Total estimated MSU costs amounted to € 815,087 per annum. Teleneurological assessment reduced overall costs by 11.7%. Conclusion: This analysis provides a framework of determinants and considerations to be addressed during the design process of a novel MSU program in order to balance stroke care improvements with the sustainable use of scarce resources