168 research outputs found

    Distance-Sensitive Planar Point Location

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    Let S\mathcal{S} be a connected planar polygonal subdivision with nn edges that we want to preprocess for point-location queries, and where we are given the probability γi\gamma_i that the query point lies in a polygon PiP_i of S\mathcal{S}. We show how to preprocess S\mathcal{S} such that the query time for a point~pPip\in P_i depends on~γi\gamma_i and, in addition, on the distance from pp to the boundary of~PiP_i---the further away from the boundary, the faster the query. More precisely, we show that a point-location query can be answered in time O(min(logn,1+logarea(Pi)γiΔp2))O\left(\min \left(\log n, 1 + \log \frac{\mathrm{area}(P_i)}{\gamma_i \Delta_{p}^2}\right)\right), where Δp\Delta_{p} is the shortest Euclidean distance of the query point~pp to the boundary of PiP_i. Our structure uses O(n)O(n) space and O(nlogn)O(n \log n) preprocessing time. It is based on a decomposition of the regions of S\mathcal{S} into convex quadrilaterals and triangles with the following property: for any point pPip\in P_i, the quadrilateral or triangle containing~pp has area Ω(Δp2)\Omega(\Delta_{p}^2). For the special case where S\mathcal{S} is a subdivision of the unit square and γi=area(Pi)\gamma_i=\mathrm{area}(P_i), we present a simpler solution that achieves a query time of O(min(logn,log1Δp2))O\left(\min \left(\log n, \log \frac{1}{\Delta_{p}^2}\right)\right). The latter solution can be extended to convex subdivisions in three dimensions

    Integrated immunovirological profiling validates plasma SARS-CoV-2 RNA as an early predictor of COVID-19 mortality.

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    peer reviewedDespite advances in COVID-19 management, identifying patients evolving toward death remains challenging. To identify early predictors of mortality within 60 days of symptom onset (DSO), we performed immunovirological assessments on plasma from 279 individuals. On samples collected at DSO11 in a discovery cohort, high severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral RNA (vRNA), low receptor binding domain–specific immunoglobulin G and antibody-dependent cellular cytotoxicity, and elevated cytokines and tissue injury markers were strongly associated with mortality, including in patients on mechanical ventilation. A three-variable model of vRNA, with predefined adjustment by age and sex, robustly identified patients with fatal outcome (adjusted hazard ratio for log-transformed vRNA = 3.5). This model remained robust in independent validation and confirmation cohorts. Since plasma vRNA’s predictive accuracy was maintained at earlier time points, its quantitation can help us understand disease heterogeneity and identify patients who may benefit from new therapies
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