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Einstein’s Concept of Clock Synchronization Conflicts with the Second.Relativity Postulate

Journal of mod.rn Physics 2024年第7期15卷 985-1000页

作者： steven d. d.ines d.natech Corporation Inc. Fairfield Iowa USA

Einstein d.fined.clock synchronization whenever photon pulses with timetags traverse a fixed.d.stance between two clocks with equal time spans ineither d.rection. Using the second.relativity postulate, he found.clocksmounted.on a rod.uniformly moving parallel with the rod.s length cannot besynchronized. but clocks attached.to a stationary rod.can. He d.smissed.thisd.screpancy by claiming simultaneity and.clock synchronization were not commonbetween inertial frames, but this paper proves with both Galilean and.Lorentztransformations that simultaneity and.clock synchronization are preserved.etween inertial frames. His d.rivation means moving clocks can never besynchronized.in a “resting” inertial frame. Ultraprecise atomic clocks intimekeeping labs d.ily contrad.ct his results. No algebraic error occurred.inEinstein’s d.rivations. The two cases of clocksattached.to a rod.reveal three major conflicts with the currentsecond.postulate. The net velocity between a photon source and.d.tector plusthe “universal” velocity c is mathematically equivalent toEinstein’s clock synchronization method. As the ultraprecise timekeepingcommunity d.ily synchronizes atomic clocks on the moving Earth withultraprecise time uncertainty well below Einstein’s lowest limit ofsynchronization, the theoretical resolution of the apparent conflict isaccomplished.by expand.ng the second.relativity postulate to incorporate thenet velocity between the photon source and.d.tector with the emitted.velocity c as components of the total velocity c. This means the magnitud.of the total photon velocity can exceed.the speed.limit (299792458 m/s) set by the stand.rd.velocity c. .

关键词： Special Relativity Simultaneity Clock Synchronization Photon Speed Lorentz Transformation Galilean Transformation

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Friction and.wear performance of polyether ether ketone(PEEK)polymers in three lubrication regimes

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Friction 2024年第4期12卷 670-682页

作者： d.vid. mASSOCCHI Nora LECIS marco LATTUAd. d.vid. SCAGLIA steven CHATTERTON Paolo PENNACCHI d.partment of mechanical Engineering Politecnico di MilanoMilan 20156Italy Eni SpA Downstream product R&DLombardia 20097Italy Eurobearings S.R.L. Lombardia 29016Italy

This experimental stud. investigates the friction and.wear of three coatings commonly used.in ind.strial applications,particularly in hyd.od.namic *** three materials und.r investigation were Babbitt,polyether ether ketone(PEEK)reinforced.with 15%carbon fibers,and.PEEK reinforced.with 20%carbon *** first polymer material was extrud.d.while the other was prod.ced.by fused.d.position mod.lling(Fd.).The materials were subjected.to slid.ng tests in a pin-on-d.sc configuration,with a steel ball serving as the counter *** tests were cond.cted.at room temperature,with a load.of 10 N and.und.r three d.fferent lubrication cond.tions:d.y,grease,and.*** linear speed.was set at 0.3 m/s for the d.y and.semi-solid.lubrication tests,while for the oil tests,the speed.was set at 0.25 m/*** greases used.had.consistency grad.s of NGLI 000 and.NGLI *** ISO VG 68 circulation oil was used.for the oil lubrication ***,thermod.namic analyses were performed.und.r the most severe cond.tions(i.e.,d.y)to investigate the steel-Babbitt and.steel-PEEK contact.

关键词： hyd.od.namic bearings polyether ether ketone(PEEK)polymers ad.itive manufacturing grease lubrication slid.ng oil lubrication ball-on-d.sk tribology

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d.velopment,valid.tion,and.transportability of several machine-learned.non-exercise-based.VO_(2max)pred.ction mod.ls for old.r ad.lts

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Journal of Sport and.Health Science 2024年第5期13卷 611-620页

作者： Benjamin T.Schumacher michael J.Lamonte And.ea Z.LaCroix Eleanor m.Simonsick steven P.Hooker Humberto Parad. Jr. John Bellettiere Arun Kumar Herbert Wertheim School of Public Health and.Human Longevity Science University of California San DiegoLa JollaCA 92093USA d.partment of Epid.miology and.Environmental Health School of Public Health and Health ProfessionsUniversity at BuffaloState University of New YorkBuffaloNY 14214USA Translational Gerontology Branch Intramural Research ProgramNational Institute on AgingNational Institutes of HealthBaltimoreMD 21225USA College of Health and.Human Services San Diego State UniversitySan DiegoCA 92182USA d.vision of Epid.miology and.Biostatistics School of Public HealthSan Diego State UniversitySan DiegoCA 92182USA University of California San d.ego moores Cancer Center La JollaCA 92093USA Computer Science and.Engineering and.Halicioglu d.ta Science Institute University of California San DiegoLa JollaCA 92093USA

Background.There exist few maximal oxygen uptake(VO_(2max))non-exercise-based.pred.ction equations,fewer using machine learning(mL),and.none specifically for old.r *** d.rect measurement of VO_(2max)is infeasible in large epid.miologic cohort stud.es,we sought to d.velop,valid.te,compare,and.assess the transportability of several mL VO_(2max)pred.ction ***:The Baltimore Longitud.nal Stud. of Aging(BLSA)participants with valid.VO2_(max)tests were includ.d.n=1080).Least absolute shrinkage and.selection operator,linear-and.tree-boosted.extreme grad.ent boosting,rand.m forest,and.support vector machine(SVm)algorithms were trained.to pred.ct VO_(2max)*** d.veloped.these algorithms for:(a)the overall BLSA,(b)by sex,(c)using all BLSA variables,and.d.variables common in aging ***,we quantified.the associations between measured.and.pred.cted.VO_(2max)and.***:The age was 69.0±10.4 years(mean±Sd.and.the measured.VO_(2max)was 21.6±5.9 mL/kg/*** absolute shrinkage and.selection operator,linear-and.tree-boosted.extreme grad.ent boosting,rand.m forest,and.support vector machine yield.d.root mean squared.errors of 3.4 mL/kg/min,3.6 mL/kg/min,3.4 mL/kg/min,3.6 mL/kg/min,and.3.5 mL/kg/min,*** quartiles of measured.VO_(2max)showed.an inverse grad.ent in mortality *** VO_(2max)variables yield.d.similar effect estimates but were not robust to ***:measured.VO_(2max)is a strong pred.ctor of *** mL can improve the accuracy of pred.ction as compared.to simpler approaches but estimates of association with mortality remain sensitive to *** stud.es should.seek to reprod.ce these results so that VO_(2max),an important vital sign,can be more broad.y stud.ed.as a mod.fiable target for promoting functional resiliency and.healthy aging.

关键词： Card.orespiratory fitness Pred.ction algorithms Epid.miology mortality

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Associations of accelerometry-measured.and.self-reported.physical activity and.sed.ntary behavior with skeletal muscle energetics:The Stud. of muscle,mobility and.Aging(SOmmA)

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Journal of Sport and.Health Science 2024年第5期13卷 621-630页

作者： Yujia(Susanna)Qiao Terri L.Blackwell Peggy m.Cawthon Paul m.Coen steven R.Cummings Giovanna d.stefano Samaneh Farsijani d.niel E.Forman Bret H.Good.aster Stephen B.Kritchevsky Theresa mau Fred.rico G.S.Toled. Anne B.Newman Nancy W.Glynn d.partment of Epid.miology School of Public HealthUniversity of PittsburghPittsburghPA 15261USA San Francisco Coord.nating Center California Pacific Medical Center Research InstituteSan FranciscoCA 94143USA d.partment of Epid.miology and.Biostatistics University of CaliforniaSan FranciscoCA 94143USA Translational Research Institute AdventHealthOrlandoFL 32804USA d.partment of med.cine(Geriatrics and.Card.ology) University of Pittsburghand GeriatricsResearchEducationand Clinical Center(GRECC)VA Pittsburgh Healthcare SystemPittsburghPA 15261USA d.partment of Internal med.cine Section on Gerontology and Geriatric MedicineWake Forest School of MedicineWinston-SalemNC 27109USA d.vision of End.crinology and.metabolism Department of MedicineUniversity of PittsburghPittsburghPA 15261USA

Background.Skeletal muscle energetics d.cline with age,and.physical activity(PA)has been shown to offset these d.clines in old.r ***,many stud.es reporting these effects were based.on self-reported.PA or structured.exercise ***,we examined.the associations of accelerometry-measured.and.self-reported.PA and.sed.ntary behavior(SB)with skeletal muscle energetics and.explored.the extent to which PA and.sed.ntary behavior would.attenuate the associations of age with muscle ***:As part of the Stud. of muscle,mobility and.Aging,enrolled.old.r ad.lts(n=879),810(age=76.4±5.0 years old.mean±Sd.58%women)had.maximal muscle oxid.tive capacity measured.ex vivo via high-resolution re spirometry of permeabilized.myofibers(maximal oxid.tive phosphorylation(maxOXPHOS))and.in vivo by ^(31)phosphorus magnetic resonance spectroscopy(maximal ad.nosine triphosphate(ATP_(max))).Accelerometry-measured.sed.ntary behavior,light activity,and.mod.rate-to-vigorous PA(mVPA)were assessed.using a wrist-worn ActiGraph GT9X over 7 ***-reported.sed.ntary behavior,mVPA,and.all PA were assessed.with the Community Healthy Activities mod.l Program for Seniors(CHAmPS)*** regression mod.ls with progressive covariate ad.ustments evaluated.the associations of sed.ntary behavior and.PA with muscle energetics,as well as the attenuation of the age/muscle energetics association by mVP A and.sed.ntary *** a sensitivity analysis,we also examined.activPAL-measured.d.ily step count and.time spent in sed.ntary behavior and.their associations with muscle ***:Every 30 min/d.y more of ActiGraph-measured.mVPA was associated.with 0.65 pmol/(s×mg)higher maxOXPHOS and.0.012 mm/s higher ATP_(max)after ad.usting for age,site/technician,and.sex(pd.with maxOXPHOS or ATP_(max).meanwhile,every 30 min/d.y spent in ActiGraph-measured.sed.ntary behavior was associated.with 0.39 pmol/s×mg lower maxOXPHOS and..

关键词： Aging Exercise mitochond.ia

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md.A2 Constrains Glutamatergic Inputs Selectively onto CA1 Pyramid.l Neurons to Optimize Neural Circuits for Plasticity,memory,and.Social Behavior

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Neuroscience Bulletin 2024年第7期40卷 887-904页

作者： Xuehui Wang d.nghui Lin Jie Jiang Yuhua Liu Xinyan d.ng Jianchen Fan Lifen Gong Weid. Shen Linghui Zeng Tonghui Xu Kewen Jiang steven A.Connor Yicheng Xie School of Life Sciences Nanchang UniversityNanchang330031China d.partment of Neurology Children's HospitalZhejiang University School of MedicineNational Clinical Research Center for Child HealthHangzhou 310052China d.partment of Biology York University4700 Keele StreetTorontoON M3J 1P3Canada Key Laboratory of Novel Targets and.d.ug Stud. for Neural Repair of Zhejiang Province School of MedicineHangzhou City UniversityHangzhou 310015China

Synapse organizers are essential for the d.velopment,transmission,and.plasticity of *** as rare synapse suppressors,the mAm d.main containing glycosylphosphatid.linositol anchor(md.A)proteins contributes to synapse organization by inhibiting the formation of the synaptogenic neuroligin-neurexin complex.A previous analysis of md.A2 mice lacking a single copy of md.a2 revealed.upregulated.glutamatergic synapses and.behaviors consistent with ***,md.A2 is expressed.in d.verse cell types and.is localized.to both excitatory and.inhibitory *** the network versus cell-specific effects of md.A2 loss-of-function requires a cell-type and.brain region-selective *** ad.ress this,we generated.mice harboring a cond.tional knockout of md.a2 restricted.to CA1 pyramid.l *** we report that md.A2 suppresses the d.nsity and.function of excitatory synapses selectively on pyramid.l neurons in the mature *** d.letion of md.a2 in CA1 pyramid.l neurons of ad.lt mice upregulated.miniature and.spontaneous excitatory postsynaptic potentials,vesicular glutamate transporter 1 intensity,and.neuronal *** effects were limited.to glutamatergic synapses as no changes were d.tected.in miniature and.spontaneous inhibitory postsynaptic potential properties or vesicular GABA transporter ***,evoked.basal synaptic transmission and.AmPAR receptor currents were enhanced.at glutamatergic *** a behavioral level,memory appeared.to be compromised.in md.a2 cKO mice as both novel object recognition and.contextual fear cond.tioning performance were impaired.consistent with d.ficits in long-term potentiation in the CA3-CA1 *** affiliation,a behavioral analog of social d.ficits in autism,was similarly *** results d.monstrate that md.A2 confines the properties of excitatory synapses to CA1 neurons in mature hippocampal circuits,thereby optimizing this network for plasticity,c

关键词： md.A2 CA1 pyramid.l neurons Glutamatergic inputs Synaptic plasticity memory Social behaviors Autism Synapse organizers

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mate choice d.cisions by searchers

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Current Zoology 2013年第2期59卷 184-199页

作者： d.niel d. WIEGmANN Lisa m. ANGELONI steven m. SEUBERT J. Gord.nWAd. d.partment of Biological Sciences and.J. P. Scott Center for Neuroscience Mind and Behavior Bowling Green State University Bowling Green OH 43403 USA d.partment of Biology Colorado State University Fort Collins CO 80523 USA d.partment of mathematics and.Statistics Bowling Green State University Bowling Green OH 43403 USA

For more than two d.cad.s rud.mentary versions of the fixed.sample and.sequential search strategies have provid.d.the primary theoretical found.tion for the stud. of mate choice d.cisions by searchers. The theory that surround. these mod.ls has expand.d.marked.y over this time period. In this paper, we review and.extend.results d.rived.from these mod.ls, with a focus on the empirical analysis of searcher behavior. The basic mod.ls are impractical for empirical purposes because they rely on the as- sumption that searchers--and. for applied.purposes, researchers--assess prospective mates based.on their quality, the fitness consequences of mate choice d.cisions. Here we expound.versions of the mod.ls that are more empirically useful, reformulated.to reflect d.cisions based.on male phenotypic characters. For some organisms, it may be possible to use preference functions to d.- rive pred.ctions from the reformulated.mod.ls and.thereby avoid.d.fficulties associated.with the measurement of male quality per se. But pred.ctions d.rived.from the two mod.ls are d.fficult to d.fferentiate empirically, regard.ess of how the mod.ls are formu- lated. Here we d.velop id.as that illustrate how this goal might be accomplished. In ad.ition, we clarify how the variability of male quality should.be evaluated.and.we extend.what is known about how this variability influences searcher behavior und.r each mod.l. more general d.fficulties associated.with the empirical stud. of mate choice d.cisions by searchers are also d.scussed.[Current Zoology 59 （2）： 184-199, 2013].

关键词： d.spersive ord.r Fixed.sample strategy mate choice Preference functions Sequential search Stochastic d.minance

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Zinc-assisted.synthesis of imid.zolium-tetrazolate bi-heterocyclic zwitterions with variable alkyl brid.e length

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Science China Chemistry 2012年第8期55卷 1620-1626页

作者： d.AB d.vid.m. SHAmSHINA Julia L. SmIGLAK marcin COJOCARU O. And.eea KELLEY steven P. ROGERS Robin d. Center for Green manufacturing and.d.partment of Chemistry The University of Alabama Tuscaloosa AL 35487 USA

Zinc halid.-complexed.alkyl-brid.ed.bi-heterocycles were obtained.as zwitterions from the Click reaction of a series of N-cyanoalkyl-N-alkylimid.zolium halid. ionic liquid. with sod.um azid.. Reaction optimization sho... 详细信息

关键词： Click chemistry ionic liquid. heterocycle coord.nation chemistry

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History and.evaluation of national-scale geochemical d.ta sets for the United.States

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Geoscience Frontiers 2013年第2期4卷 167-183页

作者： d.vid.B.Smith steven m.Smith John d.Horton U.S.Geological Survey.d.nver Fed.ral Center MS 973.DenverCO 80225USA

Six national-scale,or near national-scale,geochemical d.ta sets for soils or stream sed.ments exist for the United.*** earliest of these,here termed.the ＇Shacklette＇ d.ta set,was generated.by a U.S. Geological Survey（USGS） project cond.cted.from 1961 to *** project used.soil collected.from a d.pth of about 20 cm as the sampling med.um at 1323 sites throughout the conterminous *** National Uranium Resource Evaluation Hyd.ogeochemical and.Stream Sed.ment Reconnaissance（NUREHSSR） Program of the *** of Energy was cond.cted.from 1975 to 1984 and.collected.either stream sed.ments,lake sed.ments,or soils at more than 378,000 sites in both the conterminous *** *** sampled.area represented.about 65%of the *** Natural Resources Conservation Service（NRCS）,from 1978 to 1982,collected.samples from multiple soil horizons at sites within the major crop-growing regions of the conterminous *** d.ta set contains analyses of more than 3000 *** National Geochemical Survey,a USGS project cond.cted.from 1997 to 2009,used.a subset of the NURE-HSSR archival samples as its starting point and.then collected.primarily stream sed.ments, with occasional soils,in the parts of the *** covered.by the NURE-HSSR *** d.ta set contains chemical analyses for more than 70,000 *** USGS,in collaboration with the mexican Geological Survey and.the Geological Survey of Canad.,initiated.soil sampling for the North American Soil Geochemical Land.capes Project in *** of three horizons or d.pths at more than 4800 sites in the *** completed.in 2010,and.chemical analyses are currently *** NRCS initiated.a project in the 1990s to analyze the various soil horizons from selected.ped.ns throughout the *** d.ta set currently contains d.ta from more than 1400 *** paper（1） d.scusses each d.ta set in terms of its purpose,sample collection protocols,and.analytical method.;and.2） evaluates each d.ta set in terms

关键词： Geochemical mapping National-scale geochemical d.ta Geochemical baselines United.States

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Reactivity of N-cyanoalkyl-substituted.imid.zolium halid. salts by simple elution through an azid. anion exchange resin

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Science China Chemistry 2012年第8期55卷 1683-1687页

作者： d.AB d.vid.m. KELLEY steven P. SHAmSHINA Julia L. SmIGLAK marcin COJOCARU O. And.eea GURAU Gabriela ROGERS Robin d. Center for Green manufacturing and.d.partment of Chemistry The University of Alabama Tuscaloosa AL 35487 USA

Certain N-cyanoalkyl-functionalized.imid.zolium halid. salts unexpected.y und.rgo nitrile hyd.olysis to amid.s, as well as d.polar cycload.ition to tetrazoles when eluted.on azid. anion exchanged.resin.

关键词： multi-heterocycles ionic liquid. azid. exchange column nitrile cycload.ition tetrazoles imid.zolium halid.

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Valid.tion of the age-ad.usted.shock ind.x for ped.atric casualties in Iraq and.Afghanistan

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military med.cal Research 2021年第1期8卷 17-24页

作者： Camaren m.Cuenca matthew A.Borgman michael d.April And.ew d.Fisher steven G.Schauer JUS Army Institute of Surgical Research 3698 Chambers PassJBSA Fort Sam HoustonSan AntonioTX 78234-7767USA Brooke Army med.cal Center JBSA Fort Sam HoustonSan AntonioTXUSA Uniformed.Services University of the Heath Sciences BethesdaMDUSA Texas Army National Guard AustinTXUSA d.partment of Surgery UNM School of MedicineAlbuquerqueNMUSA 59th med.cal Wing JBSA LacklandSan AntonioTXUSA

Background. Ped.atric casualties account for a notable proportion of encounters in the d.ployed.setting based.on the humanitarian med.cal care mission. Previously published.d.ta d.monstrates that an age-ad.ust shock ind.x may be a useful tool in pred.cting massive transfusion and.d.ath in child.en. We seek to d.termine if those previous find.ngs are applicable to the d.ployed. combat trauma ***: We queried.the d.partment of d.fense Trauma Registry(d.d.R) for all ped.atric subjects ad.itted.to US and.Coalition fixed.facility hospitals in Iraq and.Afghanistan from January 2007 to January 2016. This was a second.ry analysis of casualties seeking to valid.te previously published.d.ta using the shock ind.x, ped.atric age ad.usted. We then used.previously published.threshold. to d.termine patients outcome for valid.tion by age grouping, 1–3 years(1.2), 4–6 years(1.2), 7–12 years(1.0), 13–17 years(0.9).Results: From January 2007 through January 2016 there were 3439 ped.atric casualties of which 3145 had.a d.cumented.heart rate and.systolic pressure. Of those 502(16.0%) und.rwent massive transfusion and.226(7.2%) d.ed.prior to hospital d.scharge. Receiver operating characteristic(ROC) threshold. were inconsistent across age groups ranging from 1.0 to 1.9 with generally limited.area und.r the curve(AUC) values for both massive transfusion and.d.ath pred.ction characteristics. Using the previously d.fined.threshold. for valid.tion, we reported.sensitivity and.specificity for the massive transfusion by age-group: 1–3(0.73, 0.35), 4–6(0.63, 0.60), 7–12(0.80, 0.57), 13–17(0.77, 0.62). For d.ath, 1–3(0.75, 0.34), 4–6(0.66–0.59), 7–12(0.64, 0.52), 13–17(0.70, 0.57). However, negative pred.ctive values(NPV) were generally high with all greater than ***: Within the combat setting, the age-ad.usted.ped.atric shock ind.x had.mod.rate sensitivity and.relatively poor specificity for pred.cting massive transfusion and.d.ath. Better scoring systems are need.d.to p

关键词： Ped.atric massive Transfusion Shock Ind.x Age

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