Interpersonal Status Systems. An Inquiry into Social Networks and Status Dynamics in Schools, Science, and Hollywood

Status systems—vertical orders among persons according to differences in social recognition—are a ubiquitous feature of human societies. Vast streams of research developed to explore how status structures social life. This thesis proposes a unified framework for studying the interplay between social status and social networks. The framework highlights the importance of contextual characteristics for the emergence of status systems in various settings and complements approaches that focus on how individuals gain and perpetuate status. Theoretical expectations derived from this perspective are tested by applying a combination of exponential random graph models and other network-analytical tools to three different empirical settings. The first application investigates whether the structure of friendships and status ascriptions among more than 23,000 adolescents is sensitive to contextual characteristics such as the size or demographic composition of classrooms and grade levels. The second study examines collaboration networks among more than 7,000 neuroblastoma researchers over 40 years. Here, the investigation focuses on changes in the stratification and segregation of collaboration networks as a scientific field grows and matures. Similarly, the third study investigates the interplay between culture, status, and networks among Hollywood filmmakers from 1930 through 2000 by using information on artistic references and collaborations of more than 13,000 filmmakers retrieved from the Internet movie database (IMDb). The results illustrate that the link between status and networks intensifies under certain contextual conditions. One key finding is that larger contexts exhibit networks marked by status recognition in all empirical settings: larger school classes and grade levels produce leading crowds more often than smaller ones, the scientific field of neuroblastoma research developed an elite of researchers as it grew, and social recognition is distributed increasingly unequal during periods in which Hollywood attracted more filmmakers. The thesis closes by comparing the different settings in greater detail and by discussing directions for future research

Open source software in quantum computing

Open source software is becoming crucial in the design and testing of quantum algorithms. Many of the tools are backed by major commercial vendors with the goal to make it easier to develop quantum software: this mirrors how well-funded open machine learning frameworks enabled the development of complex models and their execution on equally complex hardware. We review a wide range of open source software for quantum computing, covering all stages of the quantum toolchain from quantum hardware interfaces through quantum compilers to implementations of quantum algorithms, as well as all quantum computing paradigms, including quantum annealing, and discrete and continuous-variable gate-model quantum computing. The evaluation of each project covers characteristics such as documentation, licence, the choice of programming language, compliance with norms of software engineering, and the culture of the project. We find that while the diversity of projects is mesmerizing, only a few attract external developers and even many commercially backed frameworks have shortcomings in software engineering. Based on these observations, we highlight the best practices that could foster a more active community around quantum computing software that welcomes newcomers to the field, but also ensures high-quality, well-documented code.Comment: 22 pages, 4 figure

A scalable elliptic solver with task-based parallelism for the SpECTRE numerical relativity code

Elliptic partial differential equations must be solved numerically for many problems in numerical relativity, such as initial data for every simulation of merging black holes and neutron stars. Existing elliptic solvers can take multiple days to solve these problems at high resolution and when matter is involved, because they are either hard to parallelize or require a large amount of computational resources. Here we present a new solver for linear and non-linear elliptic problems that is designed to scale with resolution and to parallelize on computing clusters. To achieve this we employ a discontinuous Galerkin discretization, an iterative multigrid-Schwarz preconditioned Newton-Krylov algorithm, and a task-based parallelism paradigm. To accelerate convergence of the elliptic solver we have developed novel subdomain-preconditioning techniques. We find that our multigrid-Schwarz preconditioned elliptic solves achieve iteration counts that are independent of resolution, and our task-based parallel programs scale over 200 million degrees of freedom to at least a few thousand cores. Our new code solves a classic black-hole binary initial-data problem faster than the spectral code SpEC when distributed to only eight cores, and in a fraction of the time on more cores. It is publicly accessible in the next-generation SpECTRE numerical relativity code. Our results pave the way for highly-parallel elliptic solves in numerical relativity and beyond.Comment: 24 pages, 18 figures. Results are reproducible with the ancillary input file

Worldtube excision method for intermediate-mass-ratio inspirals: scalar-field model in 3+1 dimensions

Binary black hole simulations become increasingly more computationally expensive with smaller mass ratios, partly because of the longer evolution time, and partly because the lengthscale disparity dictates smaller time steps. The program initiated by Dhesi et al. (arXiv:2109.03531) explores a method for alleviating the scale disparity in simulations with mass ratios in the intermediate astrophysical range ($10^{-4} \lesssim q \lesssim 10^{-2}$), where purely perturbative methods may not be adequate. A region ("worldtube") much larger than the small black hole is excised from the numerical domain, and replaced with an analytical model approximating a tidally deformed black hole. Here we apply this idea to a toy model of a scalar charge in a fixed circular geodesic orbit around a Schwarzschild black hole, solving for the massless Klein-Gordon field. This is a first implementation of the worldtube excision method in full 3+1 dimensions. We demonstrate the accuracy and efficiency of the method, and discuss the steps towards applying it for evolving orbits and, ultimately, in the binary black-hole scenario. Our implementation is publicly accessible in the SpECTRE numerical relativity code.Comment: 19 pages, 10 figure

Prevalence and predictors of video game addiction: a study based on a national representative sample of gamers

Video gaming has become a popular leisure activity in many parts of the world, and an increasing number of empirical studies examine the small minority that appears to develop problems as a result of excessive gaming. This study investigated prevalence rates and predictors of video game addiction in a sample of gamers, randomly selected from the National Population Registry of Norway (N =3389). Results showed there were 1.4 % addicted gamers, 7.3 % problem gamers, 3.9 % engaged gamers, and 87.4 % normal gamers. Gender (being male) and age group (being young) were positively associated with addicted-, problem-, and engaged gamers. Place of birth (Africa, Asia, South- and Middle America) were positively associated with addicted- and problem gamers. Video game addiction was negatively associated with conscientiousness and positively associated with neuroticism. Poor psychosomatic health was positively associated with problem- and engaged gaming. These factors provide insight into the field of video game addiction, and may help to provide guidance as to how individuals that are at risk of becoming addicted gamers can be identified

Social Networks and Educational Decisions: Who has Access to Social Capital and for Whom is it Beneficial?

This article investigates students' access to social capital and its role in their educational decisions in the stratified German school system. We measure social capital as the availability of highly educated adults in adolescents' and parents' social networks. Using panel data on complete friendship as well as parental networks and the educational decisions of more than 2700 students from the CILS4EU-DE dataset, we show that social networks are segregated along socio-economic differences, which restricts access to social capital for socio-economically disadvantaged students. A comparison shows that parental networks tend to be substantially more segregated than children's friendship networks. In addition, our results indicate that access to social capital is linked to academically ambitious choices-i.e., entering upper secondary school or enrolling in university. This relationship is especially pronounced for less privileged students

The Ethnic Lens: Social Networks and the Salience of Ethnicity in the School Context

Research on ethnic segregation in schools regularly assumed that ethnic homophily—the tendency to befriend same-ethnic peers, above and beyond other mechanisms of tie formation—is associated with salient ethnic boundaries. We devise a more direct test of this assumption based on a novel measure of ethno-racial group perceptions. In a network study of more than 3000 students in 39 schools of a metropolitan region in Germany, we asked students to indicate which cliques they perceived in their school grade and to describe these groups in their own words. We find that ethno-racial labels are more likely directed at larger cliques that include a higher share of Muslim students or more students with stronger ethnic identification. Still, ethno-racial labels are rarely employed, both absolutely and relative to other modes of classification. Moreover, net ethnic segregation in friendships ("ethnic homophily") and the reverse pattern in dislike relations ("ethnic heterophobia") are not associated with a more frequent use of ethno-racial labels. Our results have substantive and methodological implications for the study of social networks and diversity in educational settings

Worldtube excision method for intermediate-mass-ratio inspirals: scalar-field model in 3+1 dimensions

Binary black hole simulations become increasingly more computationally expensive with smaller mass ratios, partly because of the longer evolution time, and partly because the lengthscale disparity dictates smaller time steps. The program initiated by Dhesi et al. [Phys. Rev. D 104, 124002 (2021)] explores a method for alleviating the scale disparity in simulations with mass ratios in the intermediate astrophysical range (10−4≲q≲10−2), where purely perturbative methods may not be adequate. A region (“worldtube”) much larger than the small black hole is excised from the numerical domain, and replaced with an analytical model approximating a tidally deformed black hole. Here we apply this idea to a toy model of a scalar charge in a fixed circular geodesic orbit around a Schwarzschild black hole, solving for the massless Klein-Gordon field. This is a first implementation of the worldtube excision method in full 3+1 dimensions. We demonstrate the accuracy and efficiency of the method, and discuss the steps toward applying it for evolving orbits and, ultimately, in the binary black-hole scenario. Our implementation is publicly accessible in the spectre numerical relativity code