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Stability Analysis and Performance Evaluation of Additive Mixed-Precision Runge-Kutta Methods

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Communications on Applied Mathematics and Computation 2024年第1期6卷 705-738页

作者： Ben Burnett Sigal Gottlieb zachary j.Grant Center for Scientific Computing and Data Science Research UMass DartmouthNorth DartmouthMassachusettsUSA CSME Michigan State UniversityEast LansingMichiganUSA

Additive Runge-Kutta methods designed for preserving highly accurate solutions in mixed-precision computation were previously proposed and *** specially designed methods use reduced precision for the implicit computations and full precision for the explicit *** this work,we analyze the stability properties of these methods and their sensitivity to the low-precision rounding errors,and demonstrate their performance in terms of accuracy and *** develop codes in FORTRAN and julia to solve nonlinear systems of ODEs and PDEs using the mixed-precision additive Runge-Kutta(MP-ARK)*** convergence,accuracy,and runtime of these methods are *** show that for a given level of accuracy,suitably chosen MP-ARK methods may provide significant reductions in runtime.

关键词： Mixed precision Runge-Kutta methods Additive methods Accuracy

Utilization of RNA sequencing to investigate olfactory dysfunction in chronic rhinosinusitis without nasal polyps:A pilot study

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World journal of Otorhinolaryngology-Head and Neck Surgery 2024年第1期10卷 29-36页

作者： jorge A.Gutierrez III jeremy L.Barth Rodney j.Schlosser Thomas S.Edwards Timothy L.smith zachary M.Soler Department of Otolaryngology-Head and Neck Surgery Medical University of South CarolinaCharlestonSouth CarolinaUSA Department of Regenerative Medicine&Cell Biology Medical University of South CarolinaCharlestonSouth CarolinaUSA Department of Otolaryngology-Head and Neck Surgery Oregon Health&Science UniversityPortlandOregonUSA

Objectives:Prior research on olfactory dysfunction in chronic rhinosinusitis(CRS)has focused on patients with polyps and suggests that direct inflammation of the olfactory cleft mucosa plays a contributory *** purpose of this study was to evaluate gene expression in superior turbinate mucosal specimens,comparing normosmic and dysosmic CRS patients without polyps(CRSsNP).Methods:Tissue samples were obtained from the superior turbinates of patients with CRSsNP at the time of endoscopic sinus *** subsequently underwent RNA sequencing and functional analysis to investigate biological pathways associated with differentially expressed genes between dysosmic(n=7)and normosmic(n=4)***:Differential gene expression analysis comparing dysosmic and normosmic CRSsNP patients showed upregulation of 563 genes and downregulation of 327 *** stringent criteria for multiple comparisons,one upregulated gene(Immediate Early Response 3[IER3])had an false discovery rate(FDR)correction adjustedP value considered statistically significant(P<0.001,fold change 2.69).Reactome functional analysis revealed eight biological pathways significantly different between dysosmic and normosmic patients(P<0.05,FDR correction)including IL-4 and IL-13 signaling,IL-10 signaling,and rhodopsin-like ***:RNA sequencing of the superior turbinates in patients with CRSsNP can provide valuable information regarding biological pathways and genes involved in olfactory *** study supports literature suggesting that Type 2 inflammation may play a role in olfactory dysfunction in at least some patients with *** study also prompts questions regarding the role of IL-10,rhodopsin-like receptors,andIER3 in the pathogenesis of olfactory dysfunction.

关键词： chronic rhinosinusitis without nasal polyps olfactory dysfunction RNA sequencing

Sparse-Grid Implementation of Fixed-Point Fast Sweeping WENO Schemes for Eikonal Equations

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Communications on Applied Mathematics and Computation 2024年第1期6卷 3-29页

作者： zachary M.Miksis Yong-Tao Zhang Department of Applied and Computational Mathematics and Statistics University of Notre DameNotre DameIN46556USA

Fixed-point fast sweeping methods are a class of explicit iterative methods developed in the literature to efficiently solve steady-state solutions of hyperbolic partial differential equations(PDEs).As other types of fast sweeping schemes,fixed-point fast sweeping methods use the Gauss-Seidel iterations and alternating sweeping strategy to cover characteristics of hyperbolic PDEs in a certain direction simultaneously in each sweeping *** resulting iterative schemes have a fast convergence rate to steady-state ***,an advantage of fixed-point fast sweeping methods over other types of fast sweeping methods is that they are explicit and do not involve the inverse operation of any nonlinear local ***,they are robust and flexible,and have been combined with high-order accurate weighted essentially non-oscillatory(WENO)schemes to solve various hyperbolic PDEs in the *** multidimensional nonlinear problems,high-order fixed-point fast sweeping WENO methods still require quite a large amount of computational *** this technical note,we apply sparse-grid techniques,an effective approximation tool for multidimensional problems,to fixed-point fast sweeping WENO methods for reducing their computational ***,we focus on fixed-point fast sweeping WENO schemes with third-order accuracy(Zhang et al.2006[41]),for solving Eikonal equations,an important class of static Hamilton-jacobi(H-j)*** experiments on solving multidimensional Eikonal equations and a more general static H-j equation are performed to show that the sparse-grid computations of the fixed-point fast sweeping WENO schemes achieve large savings of CPU times on refined meshes,and at the same time maintain comparable accuracy and resolution with those on corresponding regular single grids.

关键词： Fixed-point fast sweeping methods Weighted essentially non-oscillatory(WENO)schemes Sparse grids Static Hamilton-jacobi(H-j)equations Eikonal equations

Anneal-free ultra-low loss silicon nitride integrated photonics

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Light(Science & Applications) 2024年第8期13卷 1565-1577页

作者： Debapam Bose Mark W.Harrington Andrei Isichenko Kaikai Liu jiawei Wang Nitesh Chauhan zachary L.Newman Daniel j.Blumenthal Department of Electrical and Computer Engineering University of California Santa BarbaraSanta BarbaraCA 93106USA Octave Photonics LouisvilleCO 80027USA

Heterogeneous and monolithic integration of the versatile low-loss silicon nitride platform with low-temperature materials such as silicon electronics and photonics,III–V compound semiconductors,lithium niobate,organics,and glasses has been inhibited by the need for high-temperature annealing as well as the need for different process flows for thin and thick *** techniques are needed to maintain the state-of-the-art losses,nonlinear properties,and CMOS-compatible processes while enabling this next generation of 3D silicon nitride *** report a significant advance in silicon nitride integrated photonics,demonstrating the lowest losses to date for an anneal-free process at a maximum temperature 250℃,with the same deuterated silane based fabrication flow,for nitride and oxide,for an order of magnitude range in nitride thickness without requiring stress mitigation or *** report record low anneal-free losses for both nitride core and oxide cladding,enabling 1.77 dBm-1 loss and 14.9 million Q for 80 nm nitride core waveguides,more than half an order magnitude lower loss than previously reported sub 300℃ *** 800 nm-thick nitride,we achieve as good as 8.66 dBm-1 loss and 4.03 million Q,the highest reported Q for a low temperature processed resonator with equivalent device area,with a median of loss and Q of 13.9 dBm-1 and 2.59 million each *** demonstrate laser stabilization with over 4 orders of magnitude frequency noise reduction using a thin nitride reference cavity,and using a thick nitride micro-resonator we demonstrate OPO,over two octave supercontinuum generation,and four-wave mixing and parametric gain with the lowest reported optical parametric oscillation threshold per unit resonator *** results represent a significant step towards a uniform ultra-low loss silicon nitride homogeneous and heterogeneous platform for both thin and thick waveguides capable of linear and nonlinear photonic circuits and integrat

关键词： resonator thick free

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为人类健康服务的光学技术

国际人才交流 2021年第11期 61-66页

作者： [美]储扎克杨云舟(译) 中国科学技术大学

什么是科学研究?科学研究有其遵循的一定流程。首先,我们需要提出一个想法来构成初步的假设;其次,我们需要制定一个研究方案来验证假设,精心设计并开展试验;最后,通过分析试验得出的数据,我们能够揭示最初的假设是否正确。如果假设错误... 详细信息

什么是科学研究?科学研究有其遵循的一定流程。首先,我们需要提出一个想法来构成初步的假设;其次,我们需要制定一个研究方案来验证假设,精心设计并开展试验;最后,通过分析试验得出的数据,我们能够揭示最初的假设是否正确。如果假设错误,我们就必须回到第一步,修改假设,进行“再研究”,再将流程循环到底。其实,科学研究的方法可以越过纯粹科学的边界,应用到生活中的许多方面。它实际上是帮助我们应对和解决生活难题的一个视角。正因如此,我们发现,有着严谨诚实的态度并且秉持以公众利益为重的科学,掌握着世间所有问题的答案,也拥有能够改变世界的力量。

关键词：验证假设科学研究光学技术分析试验公众利益人类健康纯粹科学生活

Comparison of trigeminal lateralization with differing stimulants

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World journal of Otorhinolaryngology-Head and Neck Surgery 2024年第1期10卷 66-69页

作者： Tiffany Chen Nicolas S.Poupore Michael C.Shih Thomas S.Edwards Shaun A.Nguyen zachary M.Soler Rodney j.Schlosser Department of Otolaryngology‐Head and Neck Surgery Medical University of South CarolinaCharlestonSouth CarolinaUSA

Trigeminal-specific stimulants have been shown to activate different receptors preferentially and this likely accounts for variation in sensory *** is unclear whether trigeminal sensitivity is similar across different transient receptor potential(TRP)receptors or if dysfunction of different receptors results in differing patient ***,a prospective cohort study was conducted,consisting of trigeminal lateralization testing with three different stimulants(eucalyptol,isothiocyanate,acetic acid),olfaction testing with Sniffin'Sticks,and measurement of various patient‐reported outcome measures(PROMs).A total of 50 participants were enrolled across the olfactory *** TDI score was 27.1±8.3(range 7.0–39.5)with 38%normosmic and 62%*** trigeminal lateralization scores out of 20 in the overall cohort were 16.18(2.78)for eucalyptol,14.94(3.49)for mustard oil,and 15.28(3.68)for *** showed a significant correlation with threshold scores of Sniffin'Sticks.A significant correlation was found between acetic acid and various *** of the lateralization scores of the trigeminal stimulants correlated to each other significantly and there was no correlation to *** lack of correlation suggests that the measured sensitivity of one type of TRP receptor may not translate to similar sensitivity of the other *** investigations with TRPV1 and TRPA1 agonists are needed to corroborate our findings.

关键词： chemosensory olfaction trigeminal TRP receptor

Conservative management of spinal pathology with autologous conditioned serum: A systematic review of the literature

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World journal of Orthopedics 2024年第9期15卷 870-881页

作者： Christian j Rajkovic Matthew L Merckling Alyssa W Lee Galadu Subah Aryan Malhotra zachary D Thomas Sabrina L Zeller john V Wainwright Merritt D Kinon Department of Neurosurgery Westchester Medical CenterValhallaNY 10595United States

BACKGROUND Chronic inflammatory pain is associated with increased expression of interleukin(IL)-1,an inflammatory cytokine,and activity on its receptor(IL-1R).In response,the body produces IL-1R antagonist(IL-1Ra)to reduce this *** conditioned serum(ACS)is the only biologic therapy for spinal pathologies that enhances the action of endogenous IL-1Ra reserves to improve *** systematic review investigates the effectiveness of ACS in treating pain and dis-ability caused by spinal *** To evaluate the use of ACS as a conservative management option for spinal *** A systematic review of PubMed/Medline was performed to identify studies inve-stigating administration of ACS for treatment of any spinal *** Six articles were included,comprising 684 patients treated with epidural(n=133)or transforaminal(n=551)ACS *** had an average age of 54.0 years with slight female predominance(53.2%).The lumbar spine was most com-monly treated,with 567 patients(82.9%)receiving injections for lumbar radicu-lopathy(n=67),degenerative disc disease(DDD)(n=372),or spinal stenosis(n=128);cervical injections were performed in 109 patients(15.9%).Mean(SD)follow-up was 21.7(4.8)weeks from first ACS *** studies investigating mecha-nical lumbar and lumbar or cervical radicular pain reported significant pain re-duction at final follow-up compared to *** achieved comparable or su-perior results to lumbar epidural steroid *** events were reported in 21 patients(3.1%),with no serious adverse *** ACS injection is a safe and effective intervention for pain reduction in many spinal pathologies,including cervical and lumbar radiculopathies.

关键词： Spine Autologous conditioned serum Orthokine Regenokine Epidural steroid injection Interleukin-1 Inter-leukin-1 receptor antagonist

A GPU-Accelerated Mixed-Precision WENO Method for Extremal Black Hole and Gravitational Wave Physics Computations

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Communications on Applied Mathematics and Computation 2023年第1期5卷 97-115页

作者： Scott E.Field Sigal Gottlieb zachary j.Grant Leah F.Isherwood Gaurav Khanna University of Massachusetts Dartmouth North DartmouthMA 02747USA Department of Computational and Applied Mathematics Oak Ridge National LaboratoryOak RidgeTN 37830USA University of Rhode Island KingstonRI 02881USA

We develop and use a novel mixed-precision weighted essentially non-oscillatory(WENO)method for solving the Teukolsky equation,which arises when modeling perturbations of Kerr black *** show that WENO methods outperform higher-order finite-difference methods,standard in the discretization of the Teukolsky equation,due to the need to add dissipation for stability purposes in the *** particular,as the WENO scheme uses no additional dissipation,it is well suited for scenarios requiring long-time evolution such as the study of price tails and gravitational wave emission from extreme mass ratio *** the mixed-precision approach,the expensive computation of the WENO weights is performed in reduced floating-point precision that results in a significant speedup factor of≈*** addition,we use state-of-the-art Nvidia general-purpose graphics processing units and cluster parallelism to further accelerate the WENO *** optimized WENO solver can be used to quickly generate accurate results of significance in the field of black hole and gravitational wave *** apply our solver to study the behavior of the Aretakis charge—a conserved quantity,that if detected by a gravitational wave observatory like LIGO/Virgo would prove the existence of extremal black holes.

关键词： Numerical methods-Finite differencing Hyperbolic Partial differential equations Black holesblack holes WENO

Update in the treatment of intracranial atherosclerotic disease

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Stroke & Vascular Neurology 2020年第1期5卷 59-64页

作者： zachary R Barnard Michael j Alexander Neurosurgery Cedars-Sinai Medical CenterLos AngelesCaliforniaUSA

This review highlights the recent evolution of the imaging,medical management,surgical options and endovascular therapies for symptomatic intracranial atherosclerotic disease(ICAD).Recent imaging developments including optical coherence tomography and other modalities to assess the intracranial arteries for symptomatic ICAD are reviewed,not only to diagnose ICAD but to determine if ICAD plaques have any high-risk features for *** future developments in the treatment of ICAD are discussed,including the development of trackable drug-coated balloons for the cerebral circulation to treat primary or restenotic arteries,new iterations of self-expanding intracranial stents with easier delivery systems,and the re-examination of indirect surgical bypass techniques for *** addition to these important technological developments,however,is the evolving evidence regarding the best treatment window for these techniques and additional factors in medical management which can improve patient outcomes in this devastating pathology.

关键词： intracranial balloon arteries