Northeastern University London Repository
Not a member yet
1286 research outputs found
Sort by
A study using physical sphere-in-contact models to investigate the structure of close-packed nanoparticles supported on flat hexagonal, square and trigonal lattices
Get PDFThe tailored design of nanoparticles becomes more important with the advancement of heterogeneous catalysis and materials science. The formation of nanoparticles in catalysts with a specific geometry of the active site becomes necessary to improve activity and selectivity in catalysis. Here we have used physical sphere-in-contact models of various nanoparticles with hexagonal, square and trigonal geometries on flat close-packed surfaces to understand how the distribution of (100) and (111) sites changes as a function of nanoparticle (NP) size in a simplified model of nanoparticle supported metals. The results from this approach clearly show that in 2-layer NPs that have a hexagonal base have 2–3 times more (100) sites than the square and trigonal base NPs as a function of the number of atoms in the NP. In 3D isotropic NPs, this phenomenon is even more pronounced than the 2-layer NPs. We derive equations that estimate the number of (100), (111), the number of atoms and the aspect ratio as a function of n. These equations are important in tailoring the properties of NPs supported on close-packed metal surfaces, which may find applications in materials science, nanotechnology and catalysis
A multi-modal, asymmetric, weighted, and signed description of anatomical connectivity
Get PDFThe macroscale connectome is the network of physical, white-matter tracts between brain areas. The connections are generally weighted and their values interpreted as measures of communication efficacy. In most applications, weights are either assigned based on imaging features–e.g. diffusion parameters–or inferred using statistical models. In reality, the ground-truth weights are unknown, motivating the exploration of alternative edge weighting schemes. Here, we explore a multi-modal, regression-based model that endows reconstructed fiber tracts with directed and signed weights. We find that the model fits observed data well, outperforming a suite of null models. The estimated weights are subject-specific and highly reliable, even when fit using relatively few training samples, and the networks maintain a number of desirable features. In summary, we offer a simple framework for weighting connectome data, demonstrating both its ease of implementation while benchmarking its utility for typical connectome analyses, including graph theoretic modeling and brain-behavior associations
Protesting the Machine: Cut up Poetry Workshop
No full textCome and join us for an innovative and interactive poetry workshop in which you'll explore the connections between poetry and technological protest. Learn about the intersection of poetry, protest movements, and technology, ranging from the 19th-century Luddites to contemporary responses to Chat-GPT, and then develop your own cut-up or erasure poem with the help of a contemporary poet. This is a fun and playful session designed for both new and experienced poets, with an opportunity to showcase and share your work after the event
Towards Urban Geopolitics of Encounter: Spatial Mixing in Contested Jerusalem
No full textThe extent to which ‘geographies of encounter’ facilitate tolerance of diversity and difference has long been a source of debate in urban studies and human geography scholarship. However, to date this contestation has focused primarily on hyper-diverse cities in the global north-west. Adapting this debate to the volatile conditions of the nationally-contested city, this paper explores intergroup encounters between Israelis and Palestinians in Jerusalem. The paper suggests that in the context of hyper-polarisation of the nationally-contested urban space, the study of encounter should focus on macro-scale structural forces. In Jerusalem, we stress the role of ethnonationality and neoliberalism as key producers of its asymmetric and volatile yet highly resilient geography of intergroup encounters. In broader sense, as many cities worldwide experience a resurgence of ethnonationalism, illuminating the structural production of encounter may demarcate a broader function for reading contemporary urban geopolitics
Net freedom in Germany or over-regulation of harmful content?
Get PDFThe article focusses on the German Network Enforcement Act 2018 (NetzDG) and its amendment legislation (2021), and how it has fared so far. The article will make comparisons with the Online Safety Bill (formerly known as Online Harms Bill) and its slow passage through the United Kingdom (UK) Parliament. Both pieces of legislation cover mainly the regulation and punishment policies of social media platforms and we conclude with the question ‘does the regulation of net activity breach freedom of expression’
Hyper-cores promote localization and efficient seeding in higher-order processes
Get PDFGoing beyond networks, to include higher-order interactions of arbitrary sizes, is a major step to better describe complex systems. In the resulting hypergraph representation, tools to identify structures and central nodes are scarce. We consider the decomposition of a hypergraph in hyper-cores, subsets of nodes connected by at least a certain number of hyperedges of at least a certain size. We show that this provides a fingerprint for data described by hypergraphs and suggests a novel notion of centrality, the hypercoreness. We assess the role of hyper-cores and nodes with large hypercoreness in higher-order dynamical processes: such nodes have large spreading power and spreading processes are localized in central hyper-cores. Additionally, in the emergence of social conventions very few committed individuals with high hypercoreness can rapidly overturn a majority convention. Our work opens multiple research avenues, from comparing empirical data to model validation and study of temporally varying hypergraphs
