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作者：Zeng, Shuxi; Rosenbaum, Stacy; Alberts, Susan C.; Archie, Elizabeth A.; Li, Fan
作者单位：Duke University; University of Michigan System; University of Michigan; Duke University; Duke University; University of Notre Dame
摘要：Causal mediation analysis seeks to investigate how the treatment effect of an exposure on outcomes is mediated through intermediate variables. Although many applications involve longitudinal data, the existing methods are not directly applicable to settings where the mediator and outcome are measured on sparse and irregular time grids. We extend the existing causal mediation framework from a functional data analysis perspective, viewing the sparse and irregular longitudinal data as realization...
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作者：Zhao, Qingyuan; Ju, Nianqiao; Bacallado, Sergio; Shah, Rajen D.
作者单位：University of Cambridge; Harvard University
摘要：The coronavirus disease 2019 (COVID-19) has quickly grown from a regional outbreak in Wuhan, China, to a global pandemic. Early estimates of the epidemic growth and incubation period of COVID-19 may have been biased due to sample selection. Using detailed case reports from 14 locations in and outside mainland China, we obtained 378 Wuhan-exported cases who left Wuhan before an abrupt travel quarantine. We developed a generative model we call BETS for four key epidemiological events-Beginning o...
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作者：Glynn, Chris; Byrne, Thomas H.; Culhane, Dennis P.
作者单位：Boston University; University of Pennsylvania
摘要：Statistical models of community-level homeless rates typically assume a linear relationship to covariates. This linear model assumption precludes the possibility of inflection points in homeless rates-thresholds in quantifiable metrics of a community that, once breached, are associated with large increases in homelessness. In this paper we identify points of structural change in the relationship between homeless rates and community-level measures of housing affordability and extreme poverty. W...
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作者：Zhang, Zhenyu; Nishimura, Akihiko; Bastide, Paul; Ji, Xiang; Payne, Rebecca P.; Goulder, Philip; Lemey, Philippe; Suchard, Marc A.
作者单位：University of California System; University of California Los Angeles; Johns Hopkins University; Johns Hopkins Bloomberg School of Public Health; Universite de Montpellier; Tulane University; Newcastle University - UK; University of Oxford; University of Kwazulu Natal; Harvard University; Massachusetts Institute of Technology (MIT); Ragon Institute; Harvard University; KU Leuven; University of California System; University of California Los Angeles; University of California System; University of California Los Angeles
摘要：Inferring concerted changes among biological traits along an evolutionary history remains an important yet challenging problem. Besides adjusting for spurious correlation induced from the shared history, the task also requires sufficient flexibility and computational efficiency to incorporate multiple continuous and discrete traits as data size increases. To accomplish this, we jointly model mixed-type traits by assuming latent parameters for binary outcome dimensions at the tips of an unknown...
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作者：Qin, Jing; Deng, Geng; Ning, Jing; Yuan, Ao; Shen, Yu
作者单位：National Institutes of Health (NIH) - USA; NIH National Institute of Allergy & Infectious Diseases (NIAID); Wells Fargo Company; University of Texas System; UTMD Anderson Cancer Center; Georgetown University
摘要：For certain subtypes of breast cancer, study findings show that their level of estrogen receptor expression is associated with their risk of cancer death and also suggest a nonlinear effect on the hazard of death. A flexible form of the proportional hazards model, lambda(t vertical bar x, z) = lambda(t) exp(z(T) beta)q(x), is desirable to facilitate a rich class of covariate effect on a survival outcome to provide meaningful insight, where the functional form of q(x) is not specified except fo...
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作者：Holzer, Parker H.; Cisewski-Kehe, Jessi; Fischer, Debra; Zhao, Lily
作者单位：Yale University; University of Wisconsin System; University of Wisconsin Madison; Yale University
摘要：As the first successful technique used to detect exoplanets orbiting distant stars, the radial velocity method aims to detect a periodic Doppler shift in a stellar spectrum due to the star's motion along the line sight. We introduce a new, mathematically rigorous approach to detect such a signal that accounts for the smooth functional relationship of neighboring wavelengths in the spectrum, minimizes the role of wavelength interpolation, accounts for heteroskedastic noise and easily allows for...
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作者：White, Philip A.; Keeler, Durban G.; Rupper, Summer
作者单位：Brigham Young University; Utah System of Higher Education; University of Utah
摘要：Snow density estimates below the surface, used with airplane-acquired ice-penetrating radar measurements, give a site-specific history of snow water accumulation. Because it is infeasible to drill snow cores across all of Antarctica to measure snow density and because it is critical to understand how climatic changes are affecting the world's largest freshwater reservoir, we develop methods that enable snow density estimation with uncertainty in regions where snow cores have not been drilled. ...
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作者：Kuha, Jouni; Bukodi, Erzsebet; Goldthorpe, John H.
作者单位：University of London; London School Economics & Political Science; University of Oxford; University of Oxford
摘要：We analyse levels and trends of intergenerational social class mobility among three postwar birth cohorts in Britain and examine how much of the observed mobility or immobility in them could be accounted for by existing differences in educational attainment between people from different class backgrounds. We propose for this purpose a method which quantifies associations between categorical variables when we compare groups which differ only in the distribution of a mediating variable, such as ...
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作者：Yang, Yang; Ji, Chunlin; Deng, Ke
作者单位：Tsinghua University; Tsinghua University; Tsinghua University
摘要：Composed of a large number of subwavelength unit cells with designable geometries, metamaterials have been widely studied to achieve extraordinary advantageous and unusual optical properties. However, ordinary computer simulator requires a time-consuming fine-tuning to find a proper design of metamaterial for a specific optical property, making the design stage a critical bottleneck in large scale applications of metamaterials. This paper investigates the metamaterial design under the framewor...
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作者：Fattorini, Lorenzo; Franceschi, Sara; Marcheselli, Marzia; Pisani, Caterina; Pratelli, Luca
作者单位：University of Siena
摘要：The estimation of a surface throughout a continuum of points in a study area is addressed by means of two-phase sampling strategies. To this aim, a family of two-phase inverse distance weighting interpolators is introduced, and their design-based asymptotic properties are derived when the surface remains fixed and the number of sample points approaches infinity. In particular, conditions ensuring asymptotic unbiasedness and consistency are derived and are proven to hold for some of the most wi...
