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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

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

Facile synthesis of intra-nanogap enhanced Raman tags with different shapes

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Nano Research 2024年第9期17卷 8415-8423页

作者： Sanjun Fan Brian T.Scarpitti Zhewen Luo Abigail E.Smith Jian Ye zachary D.Schultz Department of Chemistry and Biochemistry The Ohio State UniversityColumbusOhio 43210USA School of Biomedical Engineering Shanghai Jiao Tong UniversityShanghai 200030China

Hot spot engineering in plasmonic nanostructures plays a significant role in surface-enhanced Raman scattering(SERS)for bioanalysis and cell ***,creating stable,reproducible,and strong SERS signals remains challenging due to the potential interference from surrounding chemicals and locating SERS-active analytes into hot-spot ***,we developed a straightforward approach to synthesize intra-gap nanoparticles encapsulating 4-nitrobenzenethiol(4-NBT)as a reporter molecule within these gaps to avoid outside *** made three kinds of intra-gap nanoparticles using nanorods,bipyramids,and nanospheres as cores,in which the nanorods based intra-gap nanoparticles exhibit the highest SERS *** advantage of our method is the ease of preparation of high-yield and stable intra-gap nanoparticles characterized by a short incubation time(10 min)with 4-NBT and quick synthesis without requiring an additional step to centrifuge for the purification of core *** intense localized field in the synthesized hot spots of these plasmonic gap nanostructures holds great promise as a SERS substrate for a broad range of quantitative optical applications.

关键词： hot spot engineering surface enhanced Raman scattering intra-gap nanoparticles 4-nitrobenzenethiol

Sensing the Heartbeat of China’s Dynamic Economy in Yiwu

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China Today 2024年第4期73卷 35-38页

作者： zachary LUNDQUIST 不详

Over the last 30 years,China’s small commodity market has been a big driving force for economic growth,and the city of Yiwu is the largest small commodity market in *** stong vitality today gives us a picture into ho... 详细信息

关键词： commodity China. driving

Does Ruxolitinib, in Comparison to Best Available Therapy (BAT), Improve Pruritis Symptoms in Patients with Polycythemia Vera?

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Journal of Biosciences and Medicines 2024年第3期12卷 35-43页

作者： zachary Samuel Thorogood Philadelphia College of Osteopathic Medicine Philadelphia USA

Polycythemia vera manifests as a myeloproliferative neoplasm associated with diverse symptoms, including aquagenic pruritis. This systematic review addresses the pressing need to enhance the understanding of the disease’s symptomatology and optimize treatment strategies for improved patient outcomes. The rarity and low prevalence of polycythemia vera underscore the importance of this investigation, as existing standard of care involves a multifaceted approach and significant healthcare costs. Despite advancement in therapeutic options, persistent symptoms and resistance to first-line treatments pose challenges. Ruxolitinib has emerged as a promising intervention, demonstrating clinically significant improvement for patients. This systematic review appraises three randomized controlled trials, shedding light on the efficacy of ruxolitinib and its potential to ameliorate pruritis symptoms in symptomatic patients.

关键词： Polycythemia Vera Ruxolitinib Pruritis

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

Impact of COVID-19-related lifestyle changes on diabetic macular edema

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International Journal of Ophthalmology(English edition) 2024年第1期17卷 97-106页

作者： Bryce P.Johnson Yu-Guang He zachary M.Robertson Angeline Wang Rafael L.Ufret-Vincenty Department of Ophthalmology UT Southwestern Medical CenterDallasTexas 75390-9057USA

AIM:To assess diabetic macular edema(DME)progression during the early phases of the COVID-19 pandemic,when severe societal restrictions raised the concern of possible deterioration of health in patients with systemic conditions,particularly those requiring frequent office ***:This is a multicenter retrospective chart review of 370 patients(724 eyes)with an established diagnosis of DME seen on 3 separate visits between January 2019 and July *** 1 was January 2019 to February 2020(considered pre-COVID-19),period 2 was March 2020 to December 2020(considered the height of the pandemic;highest level of pandemic-related clinical and societal regulations)and period 3 was January 2021 to July 2021(re-adjustment to the new“pandemic norms”).Main outcome measures included visual acuity,body mass index(BMI),blood pressure(BP),hemoglobin A1c(HbA1c),macular thickness,patient adherence to scheduled ophthalmology visits,and DME treatment(s)received at each *** facilitate measurement of macular thickness,each macula was divided into 9 Early Treatment Diabetic Retinopathy Study(ETDRS)-defined macular sectors as measured by OCT ***:There was no change of BMI,systolic BP,and diastolic BP between any of the time ***1c showed a very small increase from period 1(7.6%)to period 2(7.8%,P=0.015)and decreased back to 7.6%at period 3(P=0.12).Macular thickness decreased for 100%of macular *** central macular thickness decreased across all 3 periods from 329.5 to 316.6μm(P=0.0045).After analysis of multiple variables including HbA1c,BMI,adherence to scheduled appointments,different clinic centers,and treatment interventions,there was no easily identifiable subgroup of patients that experienced the increase in ***:DME doesn’t worsen during the COVID-19 pandemic,instead sustaining a very small but statistically significant *** identifying a mechanism behind our findings is beyond the scope of this study,potential explanat

关键词： COVID-19 diabetic macular edema diabetic retinopathy optical coherence tomography

Finnish Internet Influencer Builds Bridges Between China and Finland

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China Today 2024年第3期73卷 64-67页

作者： zachary G.LUNDQUIST 不详

The results of making a bet with her daughter on who would make the most popular online short videos opened up an online channel for a Finnish woman who speaks fluent Chinese to share her passion about China.

关键词： daughter speak China.

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Lessons from Baoxing

China Today 2024年第6期73卷 40-43页

作者： zachary G.LUNDQUIST 不详

IN the heart of Sichuan Province in southwest China lies a small county not many people know about,though the fluffy animals first discovered there scientifically are universally known and *** in Ya’an City is better known as the hometown of China’s giant pandas and today,it has also become a biodiversity hotspot and type locality for many endangered *** region has witnessed China’s journey in discovering,appreciating,and protecting wild*** April 22,a group of foreigners together with Chinese scholars,government officials,and panda lovers gathered in Baoxing to celebrate the 155th year of the scientific discovery of the giant panda and the 60th anniversary of the establishment of diplomatic relations between China and France.

关键词： southwest panda giant