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Approximations of expectations under infinite product measures
No full textWe are given a bounded Borel-measurable real-valued function on a product of countably many Polish spaces, and a product probability measure. We are interested in points in the product space that can be used to approximate the expected value of this function. We define two notions. A point is called a weak ϵ-approximation, where ϵ≥0, if the Dirac measure on this point, except in finitely many coordinates where another measure can be taken, gives an expected value that is ϵ-close to the original expected value. A point is called a strong ϵ-approximation if the same holds under the restriction that in those finitely many coordinates the measure is equal to the original one. We prove that both the set of weak 0-approximation points and the set of strong ϵ-approximation points, for any ϵ>0, have measure 1 under the original measure. Finally, we provide two applications: (i) in Game Theory on the minmax guarantee levels of the players in games with infinitely many players, and (ii) in Decision Theory on the set of feasible expected payoffs in infinite duration problems
On the efficiency of queueing in dynamic matching markets
No full textWe study a two-sided dynamic matching market where agents arrive randomly. An arriving agent is immediately matched if agents are waiting on the other side. Otherwise, the agent decides whether to exit the market or join a queue to wait for a match. Waiting is costly: agents discount the future and incur costs while they wait. We characterize the equilibrium and socially optimal queue sizes under first-come, first-served. Depending on the model parameters, equilibrium queues can be shorter or longer than efficiency would require them to be. Indeed, socially optimal queues may be unbounded, even if equilibrium queues are not. By contrast, when agents only incur flow costs while they wait, equilibrium queues are typically longer than socially optimal ones (cf. Baccara et al., 2020). Unlike one-sided markets, the comparison between equilibrium and socially optimal queues in two-sided markets depends on agents' time preferences
HLOB–Information persistence and structure in limit order books
No full textWe introduce a novel large-scale deep learning model for Limit Order Book mid-price changes forecasting, and we name it ‘HLOB’. This architecture (i) exploits the information encoded by an Information Filtering Network, namely the Triangulated Maximally Filtered Graph, to unveil deeper and non-trivial dependency structures among volume levels; and (ii) guarantees deterministic design choices to handle the complexity of the underlying system by drawing inspiration from the groundbreaking class of Homological Convolutional Neural Networks. We test our model against 9 state-of-the-art deep learning alternatives on 3 real-world Limit Order Book datasets, each including 15 stocks traded on the NASDAQ exchange, and we systematically characterize the scenarios where HLOB outperforms state-of-the-art architectures. Our approach sheds new light on the spatial distribution of information in Limit Order Books and on its degradation over increasing prediction horizons, narrowing the gap between microstructural modeling and deep learning-based forecasting in high-frequency financial markets
Relational in/justice journeys: revising procedural justice theory through an analysis of rape and sexual assault victims’ experiences of police investigations
Get PDFProcedural justice theory has much to say about police-citizen interactions, but the high-stakes, long-duration and quite specific nature of police investigations involving rape and sexual assault victims compel us to re-examine and re-conceptualize some of its core propositions. We draw on data from the largest national survey of rape and sexual assault victims’ experiences of the police in the United Kingdom. We find that negative officer behaviour can signal to sexual violence victims that they are not deserving of agency, connectedness, competence and care. For rape and sexual assault victims, police investigations are relational journeys of (mis)recognition and (mis)affirmation with profound impacts on victim’s personal well-being and subjective access to police safeguarding and criminal justice
Building Hamiltonian cycles in the semi-random graph process in less than 2 rounds
Get PDFThe semi-random graph process is an adaptive random graph process in which an online algorithm is initially presented an empty graph on n vertices. In each round, a vertex u is presented to the algorithm independently and uniformly at random. The algorithm then adaptively selects a vertex v, and adds the edge uv to the graph. For a given graph property, the objective of the algorithm is to force the graph to satisfy this property asymptotically almost surely in as few rounds as possible. We focus on the property of Hamiltonicity. We present an adaptive strategy which creates a Hamiltonian cycle in αn rounds, where α 1.26575
Flexible inference in heterogeneous and attributed multilayer networks
Get PDFNetworked datasets can be enriched by different types of information about individual nodes or edges. However, most existing methods for analyzing such datasets struggle to handle the complexity of heterogeneous data, often requiring substantial model-specific analysis. In this article, we develop a probabilistic generative model to perform inference in multilayer networks with arbitrary types of information. Our approach employs a Bayesian framework combined with the Laplace matching technique to ease interpretation of inferred parameters. Furthermore, the algorithmic implementation relies on automatic differentiation, avoiding the need for explicit derivations. This makes our model scalable and flexible to adapt to any combination of input data. We demonstrate the effectiveness of our method in detecting overlapping community structures and performing various prediction tasks on heterogeneous multilayer data, where nodes and edges have different types of attributes. Additionally, we showcase its ability to unveil a variety of patterns in a social support network among villagers in rural India by effectively utilizing all input information in a meaningful way
Comparing the cost of cirrhosis to other common chronic diseases: a longitudinal study in a large national insurance database
Get PDFBackground and Aims: Cirrhosis prevalence is increasing, yet costs associated with its chronic, complex care are poorly understood. The aim was to characterize the costs of care for patients with cirrhosis and compare them to other chronic diseases such as heart failure (HF) and chronic obstructive pulmonary disease (COPD), for which the public health burden is better recognized. Approach and Results: Patients enrolled in Medicare Advantage plans from a large national insurer between 2011 and 2020 with cirrhosis, HF, and COPD were identified by ICD-9/-10 codes. Costs (USD) of care were calculated per patient-month and included inpatient medical, emergency medical, pharmacy, and other costs. In all, 93,308 patients with cirrhosis, 355,520 patients with HF, and 318,949 patients with COPD were analyzed. Patients with cirrhosis, HF, and COPD had a mean (SD) age of 69.6 (9.5), 75.9 (9.7), and 72.9 (9.8) years, respectively. The most frequent etiologies were metabolic dysfunction–associated steatohepatitis (37.7%) and alcohol-associated cirrhosis (22.1%). The total monthly cost of care for patients with cirrhosis, HF, and COPD was 2491.60, and 540.40 (21.7% higher) and COPD by 3969.30, which was 59.3% (1,955.60) higher than for COPD. Conclusions: The cost of care for cirrhosis is high, significantly higher than HF and COPD. Interventions directed at optimizing care to prevent progression to cirrhosis and decompensation are likely to alleviate this public health burden
Type 2 inflammation: a Portuguese consensus using Web-Delphi and decision conferencing (INFLAT2-PT)
No full textObjectives Atopic/allergic diseases impose a growing burden on public health, affecting millions of patients worldwide. The main objective of this study was to develop a national expert consensus on relevant clinical questions related to type 2 inflammation. Methods We conducted: a comprehensive literature review with a qualitative analysis to identify the most repeated themes on the overlap of conditions; a modified 3-round Web-Delphi (or e-Delphi); and a final online decision conference. Results We included 51 studies. Following three Web-Delphi rounds, we ended up with 30 statements with a 76% overall full agreement rate, 16% agreement, 2% disagreement, and 0% full disagreement. The decision conference enabled adjustments, and the expert panel agreed unanimously on the final set of statements. The consensus used evidence synthesis, Web-Delphi, and decision conference to produce 30 statements on type 2 inflammation as a driver for multimorbidity in asthma, certain rhinitis phenotypes, atopic dermatitis, chronic rhinosinusitis with nasal polyps, and eosinophilic esophagitis grouped under five domains in underlying pathophysiology, multimorbidity, diagnosis and management, multidisciplinary management, and impact on mental health. Conclusion We expect the first Portuguese expert consensus INFLAT2-PT to promote understanding of type 2 inflammation diseases, multidisciplinary care, integrated care pathways, future research, and inform health authorities
Writing as social practice: from researchers’ to readers’ reflexivity
Get PDFA stimulating body of literature has developed methodological tools for reflexivity in practice. However, it focuses on the reflexivity of the researchers, leaving the conditions in which researchers can help readers become reflexive unaddressed. This article addresses this gap by taking decentring as a starting point. It approaches writing as a practice to foster readers’ reflexivity and introduces “writing for reflexivity” as a way for the social sciences to achieve their full potential. More specifically, it provides the conceptual foundations to tackle this problem, positions the initiatives of the authors of the running theme “Decentring Agency in World Politics: Writing for Reflexivity as a Collective Experiment” into existing literature, and offers practical guidance for researchers and teachers interested in writing for reflexivity. In all, the article builds a bridge between the methodology of writing and the methodology of reflexivity through the issues of Eurocentrism and its denial of “non-Western” agency
