arXiv subjects

Q. Long

Publications and source records attributed to Q. Long.

3 recordsLinked to original sources

arXiv2026

Self-organized hybrid scenario mediated by fishbone modes in the EAST tokamak

Self-organized hybrid scenario mediated by fishbone modes in the Experimental Advanced Superconducting Tokamak (EAST) is reported in this work. In this regime, internal transport barriers(ITBs) and a flat core safety factor profile were maintained simultaneously by fishbone modes. First,the drive of low-frequency flows by fishbone modes is clarified, which subsequently suppresses turbulence transport. Besides, fishbone-induced poloidally symmetric (m = 0) toroidal current sheets were first reported experimentally, which drive outward current redistribution that mitigates core current peaking. Together, these effects enable hybrid operation with stable ITBs and robust magnetohydrodynamic (MHD) stability, revealing a self-organized pathway for sustaining hybrid scenario for fusion reactors.

physics.plasm-ph↗

arXiv2023

Extensions of Heterogeneity in Integration and Prediction (HIP) with R Shiny Application

Multiple data views measured on the same set of participants is becoming more common and has the potential to deepen our understanding of many complex diseases by analyzing these different views simultaneously. Equally important, many of these complex diseases show evidence of subgroup heterogeneity (e.g., by sex or race). HIP (Heterogeneity in Integration and Prediction) is among the first methods proposed to integrate multiple data views while also accounting for subgroup heterogeneity to identify common and subgroup-specific markers of a particular disease. However, HIP is applicable to continuous outcomes and requires programming expertise by the user. Here we propose extensions to HIP that accommodate multi-class, Poisson, and Zero-Inflated Poisson outcomes while retaining the benefits of HIP. Additionally, we introduce an R Shiny application, accessible on shinyapps.io at https://multi-viewlearn.shinyapps.io/HIP_ShinyApp/, that provides an interface with the Python implementation of HIP to allow more researchers to use the method anywhere and on any device. We applied HIP to identify genes and proteins common and specific to males and females that are associated with exacerbation frequency. Although some of the identified genes and proteins show evidence of a relationship with chronic obstructive pulmonary disease (COPD) in existing literature, others may be candidates for future research investigating their relationship with COPD. We demonstrate the use of the Shiny application with a publicly available data. An R-package for HIP would be made available at https://github.com/lasandrall/HIP.

stat.ME↗

arXiv2023

Accounting for data heterogeneity in integrative analysis and prediction methods: An application to Chronic Obstructive Pulmonary Disease

Epidemiologic and genetic studies in chronic obstructive pulmonary disease (COPD) and many complex diseases suggest subgroup disparities (e.g., by sex). We consider this problem from the standpoint of integrative analysis where we combine information from different views (e.g., genomics, proteomics, clinical data). Existing integrative analysis methods ignore the heterogeneity in subgroups, and stacking the views and accounting for subgroup heterogeneity does not model the association among the views. To address analytical challenges in the problem of our interest, we propose a statistical approach for joint association and prediction that leverages the strengths in each view to identify molecular signatures that are shared by and specific to males and females and that contribute to the variation in COPD, measured by airway wall thickness. HIP (Heterogeneity in Integration and Prediction) accounts for subgroup heterogeneity, allows for sparsity in variable selection, is applicable to multi-class and to univariate or multivariate continuous outcomes, and incorporates covariate adjustment. We develop efficient algorithms in PyTorch. Our COPD findings have identified several proteins, genes, and pathways that are common and specific to males and females, some of which have been implicated in COPD, while others could lead to new insights into sex differences in COPD mechanisms.

stat.ME↗