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Direct-to-indirect mapping for optimal low-thrust trajectories

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Astrodynamics 2024年第1期8卷 27-46页

作者： david Ottesen Ryan P.russell Department of Aerospace Engineering and Engineering Mechanics The University of Texas at AustinAustinTexas78712USA

Optimal,many-revolution spacecraft trajectories are challenging to solve.A connection is made for a class of models between optimal direct and indirect *** transfers that minimize thrust-acceleration-squared,primer vector theory maps direct,many-impulsive-maneuver trajectories to the indirect,continuous-thrust-acceleration *** mapping algorithm is independent of how the direct solution is obtained and requires only a solver for a boundary value problem and its partial derivatives.A Lambert solver is used for the two-body problem in this *** mapping is simple because the impulsive maneuvers and co-states share the same linear space around an optimal *** numerical results,the direct coast-impulse solutions are demonstrated to converge to the indirect continuous solutions as the number of impulses and segments *** two-body design space is explored with a set of three many-revolution,many-segment examples changing semimajor axis,eccentricity,and *** first two examples involve a small change to either semimajor axis or eccentricity,and the third example is a transfer to geosynchronous *** a single processor,the optimization runtime is seconds to minutes for revolution counts of 10 to 100,and on the order of one hour for examples with up to 500 *** of these thrust-acceleration-squared solutions are good candidates to start a homotopy to a higher-fidelity minimization problem with practical constraints.

关键词： direct optimization indirect optimization impulsive maneuvers Lambert's problem two-body dynamics primer vectortheory

Hepatic angiotensin-converting enzyme 2 expression in metabolic dysfunction-associated steatotic liver disease and in patients with fatal COVID-19

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World Journal of Gastroenterology 2024年第31期30卷 3705-3716页

作者： Angus K Jacobs Steven D Morley Kay Samuel Katie morgan Lyndsey Boswell Timothy J Kendall david A Dorward Jonathan A Fallowfield Peter C Hayes John N Plevris Hepatology Laboratory University of EdinburghEdinburgh EH164SBUnited Kingdom Scottish National Blood Transfusion Service Jack Copland CentreEdinburgh EH144BEUnited Kingdom Institute for Regeneration and Repair University of EdinburghEdinburgh EH164UUUnited Kingdom Edinburgh Pathology University of EdinburghEdinburgh EH164SBUnited Kingdom

BACKGROUND Metabolic dysfunction-associated steatotic liver disease(MASLD),characterised by hepatic lipid accumulation,causes inflammation and oxidative stress accompanied by cell damage and *** injury(LI)is also frequently reported in patients hospitalised with coronavirus disease 2019(COVID-19),while preexisting MASLD increases the risk of LI and the development of COVID-19-associated *** of injury at the cellular level remain unclear,but it may be significant that severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)which causes COVID-19,uses angiotensin-converting expression enzyme 2(ACE2),a key regulator of the‘anti-inflammatory’arm of the renin-angiotensin system,for viral attachment and host cell *** To determine if hepatic ACE2 levels are altered during progression of MASLD and in patients who died with severe *** ACE2 protein levels and localisation,and histological fibrosis and lipid droplet accumulation as markers of MASLD were determined in formalin-fixed liver tissue sections across the MASLD pathological spectrum(isolated hepatocellular steatosis,metabolic dysfunction-associated steatohepatitis(MASH)+/-fibrosis,end-stage cirrhosis)and in post-mortem tissues from patients who had died with severe COVID-19,using ACE2 immunohistochemistry and haematoxylin and eosin and picrosirius red staining of total collagen and lipid droplet areas,followed by quantification using machine learning-based image pixel *** ACE2 staining is primarily intracellular and concentrated in the cytoplasm of centrilobular hepatocytes and apical membranes of bile duct ***,ACE2 protein levels are elevated in non-fibrotic MASH compared to healthy controls but not in the progression to MASH with fibrosis and in ***2 protein levels and histological fibrosis are not associated,but ACE2 and liver lipid droplet content are significantly correlated across the MASLD *** A

关键词： Metabolic dysfunction-associated steatotic liver disease Angiotensin-converting enzyme 2 Immunohistochemistry COVID-19 COVID-19-associated cholangiopathy

Severe acute respiratory syndrome coronavirus-2-related and imputable deaths in children:results from the French pediatric national registry

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World Journal of Pediatrics 2024年第6期20卷 611-620页

作者： Marguerite Lockhart-Bouron Noemie Vanel Michael Levy Anais R.Briant Etienne Javouhey Sophie Breinig Julia Dina Marion Caseris Francois Angoulvant Stephane Leteurtre morgan Recher david W.Brossier Univ.Lille CHU LilleULR 2694-METRICS:Evaluation Des Technologies de Sante Et Des Pratiques Medicales59000LilleFrance Pediatric Intensive Care Unit CHU de MarseilleMarseilleFrance Pediatric Intensive Care Unit CHU Robert-DebreAssistance Publique Hopitaux de ParisParisFrance UniversitéParis-Cite ParisFrance Biostatistics and Clinical Research Unit CHU de Caen Normandie14000CaenFrance Pediatric Intensive Care Hospices Civils de LyonLyonFrance Neonatal andPediatric IntensiveCare Unit Children's HospitalToulouseFrance Virology Department INSERM U1311 DynamicureUniv CAEN NormandieCHU de Caen14000 CaenFrance Medical School Universite Caen Normandie14000 CaenFrance Department of Pediatrics CHU Robert-DebréAssistance Publique Hopitaux de ParisParisFrance Department Women-Mother-Child Service of PediatricsLausanne University Hospital(CHUV)LausanneSwitzerland Pediatric Intensive Care Unit Réanimation Et Soins Intensifs PéediatriquesCHU de CAENAvenue de La Cote de Nacre14000 CaenFrance CHU Sainte Justine Research Center MontréalCanada

Background Severe acute respiratory syndrome coronavirus-2(SARS-CoV-2)is responsible for an important mortality rate *** aimed to evaluate the actual imputability of SARS-CoV-2 on the mortality rate associated with SARS-CoV-2-related illnesses in the pediatric intensive care unit(PICU).Secondary objectives were to identify risk factors for *** This national multicenter comparative study comprised all patients under 18 years old with positive SARS-CoV-2 polymerase chain reactions(PCRs)[acute corona virus disease 2019(COVID-19)or incidental SARS-CoV-2 infection]and/or pediatric inflammatory multisystem syndrome(PIMS)recorded in the French PICU registry(PICURe)between September 1,2021,and August 31,*** patients were classified and compared according to their living status at the end of their PICU *** patients were evaluated by four experts in the field of pediatric infectiology and/or pediatric intensive *** imputability of SARS-CoV-2 as the cause of death was classified into four categories:certain,very probable,possible,or unlikely,and was defined by any of the first three *** There were 948 patients included of which 43 died(4.5%).From this,26 deaths(67%)could be attributed to SARS-CoV-2 infection,with an overall mortality rate of 2.8%.The imputability of death to SARS-CoV-2 was considered certain in only one case(O.1%).Deceased patients suffered more often from comorbidities,especially heart disease,neurological disorders,hematological disease,cancer,and *** of the deceased patients were admitted for pediatric inflam-matory multisystem syndrome(PIMS).Mortality risk factors were male gender,cardiac comorbidities,cancer,and acute respiratorydistress *** SARS-CoV-2 mortality in the French pediatric population was *** though the imputability of SARS-Cov-2 on mortality was considered in almost two-thirds of cases,this imputability was considered certain in only one case.

关键词： Death Pediatric intensive care unit SARS-CoV-2

OPTIMAL INVERSE LQG CONTROL FOR CERTAIN ODE AND PDE STATIONARY PROCESSES

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Journal of Systems Science & Complexity 2010年第3期23卷 584-599页

作者： david L.russell Department of Mathematics Virginia Tech

Following work carried out earlier on linear-quadratic optimal control for linear finitedimensional stationary systems we report,in this article,on extension of some of those results to certaininfinite dimensional systems;in particular a class of PDE systems of elliptic *** systems arestudied in the now familiar framework developed by *** and ***,specialized to asubclass of such systems important in a variety of *** an extended example this paperstudies an optimal redistribution problem in a groundwater flow system governed by Darcy's equation,presenting both analytic and computational work related to such problems.

关键词： Elliptic PDE linear feedback control stationary system.

Cytomegalovirus-associated colitis causing diarrhea in an immunocompetent patient

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World Journal of Gastroenterology 2006年第42期12卷 6898-6899页

作者： Dan Carter david Olchovsky russell Pokroy david Ezra Internal Medicine A Sheba Medical Center Tel Hashomer Israel

Cytomegalovirus （CMV） colitis rarely occurs in immunocompetent patients. We report a case of disabling and life threatening diarrhea in an immunocompetent elderly woman due to CMV colitis. The diagnosis of CMV was based on histological examination of tissues biopsied at colonoscopy, positive CMV antigen and high CMV-lgM titer in peripheral blood samples and a good response to systemic gancyclovir treatment. We conclude that CMV should be considered in the differential diagnosis of colitis in elderly immunocompetent patients.

关键词： Cytomegalovirus Colitis Immunocompetent Diarrhea Gancyclovir

Non-Linear Matrix Completion

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Journal of Data Analysis and Information Processing 2024年第1期12卷 115-137页

作者： Fengrui Zhang Randy C. Paffenroth david Worth Worcester Polytechnic Institute Worcester MA USA

Current methods for predicting missing values in datasets often rely on simplistic approaches such as taking median value of attributes, limiting their applicability. Real-world observations can be diverse, taking stock price as example, ranging from prices post-IPO to values before a company’s collapse, or instances where certain data points are missing due to stock suspension. In this paper, we propose a novel approach using Nonlinear Matrix Completion (NIMC) and Deep Matrix Completion (DIMC) to predict associations, and conduct experiment on financial data between dates and stocks. Our method leverages various types of stock observations to capture latent factors explaining the observed date-stock associations. Notably, our approach is nonlinear, making it suitable for datasets with nonlinear structures, such as the russell 3000. Unlike traditional methods that may suffer from information loss, NIMC and DIMC maintain nearly complete information, especially in high-dimensional parameters. We compared our approach with state-of-the-art linear methods, including Inductive Matrix Completion, Nonlinear Inductive Matrix Completion, and Deep Inductive Matrix Completion. Our findings show that the nonlinear matrix completion method is particularly effective for handling nonlinear structured data, as exemplified by the russell 3000. Additionally, we validate the information loss of the three methods across different dimensionalities.

关键词： Matrix Completion Data Pipeline Machine Learning

Botryosphaeriaceae and Diaporthaceae associated with panicle and shoot blight of pistachio in California,USA

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Fungal Diversity 2014年第4期67卷 157-179页

作者： Shuai Fei Chen david P.morgan Themis J.Michailides Department of Plant Pathology University of California-Davis/Kearney Agricultural Research and Extension Center9240 South Riverbend AvenueParlierCA 93648USA China Eucalypt Research Centre(CERC) Chinese Academy of Forestry(CAF)ZhanJiang 524022GuangDong ProvinceChina

Botryosphaeria panicle and shoot blight was considered as one of the single greatest threats to the California pistachio industry in the last two decades.A large number of fungi with typical morphological characteristics of Botryosphaeriaceae and Diaporthe were collected from pistachios in 18 counties in California and deposited in our culture *** aims of this study were to identify these isolates,recognize the distribution of these fungal species and test their pathogenicity to pistachio cultivars.A total of 304 California isolates were identified based on comparisons of DNA sequence data of the ITS,TEF-1α and β-tubulin gene regions,and combined with the morphological features of the cultures and *** results showed that California isolates represent eight species of Botryosphaeriaceae and one species of *** species include Botryosphaeria dothidea,Diplodia seriata,Dothiorella iberica,***,Lasiodiplodia citricola,***,Neofusicoccum mediterraneum,*** and Diaporthe *** the Botryosphaeriaceae,86% of the isolates were identified as ***,which distributed in all the sampled *** pistachio trees,in addition to isolates from California,*** from Arizona,*** from Australia,***,*** and *** from Greece were also *** of the California fungi on pistachio cultivars,Kerman(female)and Peters(male),using a mycelium plug and conidial suspension inoculation methods showed that all these species are pathogenic to the two tested pistachio cultivars,with ***,*** being the most pathogenic species,followed by *** study represents the first comprehensive work on the species identification,distribution and pathogenicity of Botryosphaeriaceae and Diaporthe on pistachio in California.

关键词： blight cultivar California

The demands of the extra-time period of soccer:A systematic review

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Journal of Sport and Health Science 2022年第3期11卷 403-414页

作者： Adam Field Robert Joseph Naughton Matthew Haines Steve Lui Liam david Corr Mark russell Richard Michael Page Liam david Harper School of Human and Health Sciences University of HuddersfieldHuddersfieldHD13DHUK School of Social and Health Sciences Leeds Trinity UniversityBrownberrie LaneHorsforthLeedsLS185HDUK Department of Sport&Physical Activity Edge Hill UniversitySt.Helens RoadOrmskirkLancashireL394QPUK

Background:Soccer match-play is typically contested over 90 min;however,in some cup and tournament scenarios,when matches are tied,they proceed to an additional 30 min,which is termed "extra-time^(ET).This systematic review sought to appraise the literature available on 120-min of soccer-specific exercise,with a view to identifying practical recommendations and future research ***:The review was conducted according to the PRISMA *** researchers performed a systematic search of PubMed,CINAHL,and PsycINFO in May 2019,with the following keywords entered in various combinations:"soccer","football","extra-time","extra time","extratime","120 minutes","120 min","additional 30 minutes",and "additional 30 min".Results:The search yielded an initial 73 *** the screening process,11 articles were accepted for *** were subsequently organized into the following 5 categories:movement demands of ET,performance responses to ET,physiological and neuromuscular response during ET,nutritional interventions,and recovery and *** results highlighted that during competitive match-play,players cover5%-12% less distance relative to match duration(i.e.,meters per minute) during ET compared to the preceding 90 *** in technical performance(i.e.,shot speed,number of passes and dribbles) were also observed during ***,carbohydrate provision may attenuate and improve dribbling performance during ***,objective and subjective measures of recovery may be further compromised following ET when compared to 90 ***:Additional investigations are warranted to further substantiate these findings and identify interventions to improve performance during ET.

关键词： Movement demands Neuromuscular fatigue Nutritional intervention Performance Physiology

Martensitic twinning transformation mechanism in a metastable IVB element-based body-centered cubic high-entropy alloy with high strength and high work hardening rate

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Journal of Materials Science & Technology 2022年第29期124卷 217-231页

作者： Yuhe Huang Junheng Gao Vassili Vorontsov Dikai Guan russell Goodall david Dye Shuize Wang Qiang Zhu W.Mark Rainforth Iain Todd Department of Materials Science and Engineering University of SheffieldSheffield S13JDUnited Kingdom Department of Mechanical and Energy Engineering Southern University of Science and TechnologyShenzhen518055China Beijing Advanced Innovation Center for Materials Genome Engineering University of Science and Technology BeijingBeijing 100083China Department of Materials Royal School of MinesImperial College LondonLondon SW72BPUnited Kingdom

Realizing high work hardening and thus elevated strength–ductility synergy are prerequisites for the practical usage of body-centered-cubic high entropy alloys(BCC-HEAs).In this study,we report a novel dynamic strengthening mechanism,martensitic twinning transformation mechanism in a metastable refractory element-based BCC-HEA(TiZrHf)Ta(at.%)that can profoundly enhance the work hardening capability,leading to a large uniform ductility and high strength *** from conventional transformation induced plasticity(TRIP)and twinning induced plasticity(TWIP)strengthening mechanisms,the martensitic twinning transformation strengthening mechanism combines the best characteristics of both TRIP and TWIP strengthening mechanisms,which greatly alleviates the strengthductility trade-off that ubiquitously observed in BCC structural *** characterization,carried out using X-ray diffraction(XRD)and electron back-scatter diffraction(EBSD)shows that,upon straining,α”(orthorhombic)martensite transformation,self-accommodation(SA)α”twinning and mechanicalα”twinning were activated *** electron microscopy(TEM)analyses reveal that continuous twinning activation is inherited from nucleating mechanical{351}type I twins within SA“{351}”typeⅡtwinnedα”variants on{351}twinning plane by twinning transformation through simple shear,thereby accommodating the excessive plastic strain through the twinning shear while concurrently refining the grain ***,consistent high work hardening rates of 2–12.5 GPa were achieved during the entire plastic deformation,leading to a high tensile strength of 1.3 GPa and uniform elongation of 24%.Alloy development guidelines for activating such martensitic twinning transformation strengthening mechanism were proposed,which could be important in developing new BCC-HEAs with optimal mechanical performance.

关键词： Metastable high entropy alloy Work hardening rate Martensitic transformation Self-accommodating martensite Twinning transformation