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On the Features of Thermal convection in a compressible Gas

Fluid Dynamics & Materials Processing 2024年第5期20卷 957-974页

作者： Igor b.Palymskiy Physics Department Siberian State University of Telecommunications and Information SciencesNovosibirsk City630102Russia Physics Department Siberian State University of Geosystems and TechnologiesNovosibirsk City630108Russia

The fully nonlinear equations of gas dynamics are solved in the framework of a numerical approach in order to study the stability of the steady mode of Rayleigh-bénard convection in compressible,viscous and heat-conducting gases encapsulated in containers with no-slip boundaries and isothermal top and bottom *** initial linear temperature profile is assumed.A map of the possible convective modes is presented assuming the height of the region and the value of the temperature gradient as influential *** a relatively small height,isobaric convection is found to take place,which is taken over by an adiabatic mode when the height exceeds the critical value,or by a super-adiabatic mode in case of a relatively high temperature *** the adiabatic mode,convective flow develops due to adiabatic processes given a stable initial *** analytic formula for the critical height of the region is derived taking into account and neglecting the dependence of the gas viscosity on the ***,an analytic formula is obtained for the upper boundary of the region of applicability of the boussinesq approximation for incompressible *** models for compressible gases are relevant to practical situations such as the study of convective flows in spatially extended gas mixtures when dealing with safety issues related to hydrocarbons stored in gas stations.A dangerous situation arises when the tank is almost empty but some hydrocarbon is left at the bottom of the *** the presence of convective flows,the vaporized fuel is mixed with the oxidizer(air)forming a gas-vapor ***,if the volumetric concentration of fuel vapor(hydrocarbon)is in the interval between the lower and upper concentration limits of ignition,then the gas-vapor mixture becomes explosive and any accidental spark is sufficient to cause an emergency.

关键词： Rayleigh-bénard convection gas stable stratification unstable stratification temperature gradient

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Hepatitis b virus genotypes in precision medicine of hepatitis brelated hepatocellular carcinoma:Where we are now

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World Journal of Gastrointestinal Oncology 2024年第4期16卷 1097-1103页

作者： caecilia H c Sukowati Sri Jayanti Turyadi Turyadi David H Muljono claudio Tiribelli Eijkman Research center for Molecular biology Research Organization for HealthNational Research and Innovation Agency of IndonesiaJakarta 10340Indonesia Liver cancer Unit Fondazione Italiana Fegato ONLUSTrieste 34149Italy Faculty of Medicine Hasanuddin UniversityMakassar 90245South SulawesiIndonesia Faculty of Medicine and Health University of SydneySydney 2050Australia

Hepatitis b virus(HbV)infection is a major player in chronic hepatitis b that may lead to the development of hepatocellular carcinoma(Hcc).HbV genetics are diverse where it is classified into at least 9 genotypes(A to I)and 1 putative genotype(J),each with specific geographical distribution and possible different clinical outcomes in the *** diversity may be associated with the precision medicine for HbV-related Hcc and the success of therapeutical approaches against Hcc,related to different pathogenicity of the virus and host *** Editorial discusses recent updates on whether the classification of HbV genetic diversity is still valid in terms of viral oncogenicity to the Hcc and its precision medicine,in addition to the recent advances in cellular and molecular biology technologies.

关键词： Hepatitis b virus Hepatocellular carcinoma Genotypes Pathogenesis Precision medicine

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Learning to become addicted,one synapse at a time

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Neural Regeneration Research 2024年第2期19卷 401-402页

作者： Alessio Attardo Sidney b.cambridge Leibniz Institute for Neurobiology MagdeburgGermany Institute for Anatomy II Dr.Senckenberg AnatomyGoethe-University Frankfurt am MainFrankfurtGermany

Addiction has been extensively studied on many levels:from the molecular level,with various“omics”approaches(Natividad et al.,2018;Grecco et al.,2021),to the clinical level,with psychotherapy and MRI imaging(ceceli ... 详细信息

关键词： clinical therapy

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Old-growth mixed dipterocarp forests show variable losses and gains in aboveground biomass and standing carbon over forty years

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Forest Ecosystems 2024年第1期11卷 14-23页

作者： Sisira Ediriweera champika bandara Tithira Lakkana Shanika Jayasinghe David Woodbury Arun Dayanandan b.M.P.Singhakumara Xiangcheng Mi I.A.U.N.Gunatilleke c.V.S.Gunatilleke Mark SAshton Department of Science and Technology Uva Wellassa UniversityBadullaSri Lanka The Forest School Yale School of the EnvironmentYale UniversityNew HavenCT06511USA Department of Forestry and Environmental Science University of Sri JayewardenepuraNugegodaSri Lanka State Key Laboratory of Vegetation and Environmental change Institute of BotanyChinese Academy of SciencesBeijing100093China botany Department University of PeradeniyaPeradeniyaSri Lanka

background:No studies have documented long-term trends in aboveground biomass(AGb)for mixed-dipterocarp forests(MDF),the dominant rain forest type in tropical wet equatorial *** our study,we sought to document such trends over forty years across three sites representing lowland to lower montane ***:To do this,we established fifty 100 m×25 m plots in 1978 across three sites sampled along an elevation gradient,identified as mature old-growth *** measured trees for diameter at breast height that we identified to species and *** took wood samples to calculate species wood-specific *** re-measured plots in 1998 and again in ***:We show standing AGb for all sites combined to be 517.52 Mg·ha^(-1)in 1978,but this declined by 17%over 40 years to 430.11 Mg·ha^(-1).No differences exist among sites in AGb primarily because of considerable within site variation;but interactions of time with site show declines across sites were not uniform,one remained about the *** few species represented a high proportion of the AGb with the top five species comprising between 34%and 65%,depending upon site and year *** species,Mesua nagassarium,represented a disproportionately large amount of AGb and decline over time,particularly at the low elevation ***:Our results are directly relevant to estimating AGb and standing carbon sequestered in *** study is the first to demonstrate varying but overall,declining trends in amounts of AGb among forests making predictions of biomass and standing carbon in MDF difficult over wide regions.

关键词： Western ghats Shorea spp. Southeast Asia Sri Lanka Tropical rain forest Wood specific gravity

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There is more to the knee joint than just the quadriceps:A systematic review with meta-analysis and evidence gap map of hamstring strength,flexibility,and morphology in individuals with gradual-onset knee disorders

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Journal of Sport and Health Science 2024年第4期13卷 521-536页

作者： Helder S.Lopes Marina c.Waiteman Liliam b.Priore Neal R.Glaviano David M.bazett-Jones Ronaldo V.briani Fabio M.Azevedo School of Science and Technology Physical Therapy DepartmentSao Paulo State University(UNESP)Presidente Prudente 19060-900Brazil Department of Kinesiology College of AgricultureHealth and Natural ResourcesUniversity of ConnecticutStorrsCT 06269USA School of Exercise and Rehabilitation Sciences College of Health and Human ServicesUniversity of ToledoToledoOH 43606USA

background:Impairments in hamstring strength,flexibility,and morphology have been associated with altered knee biomechanics,pain,and *** the presence of these impairments in individuals with gradual-onset knee disorders is important and may indicate targets for assessment and *** systematic review aimed to synthesize the literature to determine the presence of impairments in hamstring strength,flexibility,and morphology in individuals with gradual-onset knee ***:Five databases(MEDLINE,Embase,cINAHL,SPORTDiscus,and Web of Science)were searched from inception to September *** studies comparing hamstring outcomes(e.g.,strength,flexibility,and/or morphology)between individuals with gradual-onset knee disorders and their unaffected limbs or pain-free controls were ***-analyses for each knee disorder were ***-level certainty was assessed using the Grading of Recommendations Assessment,Development,and Evaluation,and evidence gap maps were ***:Seventy-nine studies across 4 different gradual-onset knee disorders(i.e.,knee osteoarthritis(OA),patellofemoral pain(PFP),chondromalacia patellae,and patellar tendinopathy)were *** with knee OA presented with reduced hamstring strength compared to pain-free controls during isometric(standard mean difference(SMD)=-0.76,95%confidence interval(95%cI):-1.32 to-0.21)and concentric contractions(SMD=-0.97,95%cI:-1.49 to-0.45).Individuals with PFP presented with reduced hamstring strength compared to painfree controls during isometric(SMD=-0.48,95%cI:-0.82 to-0.14),concentric(SMD=-1.07,95%cI:-2.08 to-0.06),and eccentric contractions(SMD=-0.59,95%cI:-0.97 to-0.21).No differences were observed in individuals with patellar *** with PFP presented with reduced hamstring flexibility when compared to pain-free controls(SMD=-0.76,95%cI:-1.15 to-0.36).Evidence gap maps identified insufficient evidence for chondromalacia patel

关键词： chondromalacia patellae Knee flexors Knee osteoarthritis Patellar tendinopathy Patellofemoral pain

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Study of hybrid nanofluid flow in a stationary cone-disk system with temperature-dependent fluid properties

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 677-694页

作者： A.S.JOHN b.MAHANTHESH G.LORENZINI center for Mathematical Needs Department of MathematicsCHRIST(Deemed to be University)Karnataka 560029India School of Mathematical and Statistical Sciences The University of Texas Rio Grande ValleyTexas 78539U.S.A. Department of Engineering and Architecture University of ParmaParma 43124Italy

cone-disk systems find frequent use such as conical diffusers,medical devices,various rheometric,and viscosimetry *** this study,we investigate the three-dimensional flow of a water-based Ag-Mg O hybrid nanofluid in a static cone-disk system while considering temperature-dependent fluid *** the variable fluid properties affect the dynamics and heat transfer features is studied by Reynolds's linearized model for variable viscosity and chiam's model for variable thermal *** single-phase nanofluid model is utilized to describe convective heat transfer in hybrid nanofluids,incorporating the experimental *** model is developed as a coupled system of convective-diffusion equations,encompassing the conservation of momentum and the conservation of thermal energy,in conjunction with an incompressibility condition.A self-similar model is developed by the Lie-group scaling transformations,and the subsequent self-similar equations are then solved *** influence of variable fluid parameters on both swirling and non-swirling flow cases is ***,the Nusselt number for the disk surface is *** is found that an increase in the temperature-dependent viscosity parameter enhances heat transfer characteristics in the static cone-disk system,while the thermal conductivity parameter has the opposite effect.

关键词： hybrid nanofluid cone-disk system laminar flow variable fluid property Nusselt number

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Quantum correlations and entanglement in coupled optomechanical resonators with photon hopping via Gaussian interferometric power analysis

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chinese Physics b 2024年第5期33卷 204-211页

作者： Y.Lahlou b.Maroufi M.Daoud LPHE-MS Department of PhysicsFaculty of SciencesMohammed V UniversityRabatMorocco LPMS Department of PhysicsFaculty of SciencesIbn Tofail UniversityKénitraMorocco

Quantum correlations that surpass entanglement are of great importance in the realms of quantum information processing and quantum ***,for quantum systems prepared in pure states,it is difficult to differentiate between quantum entanglement and quantum ***,this indistinguishability is no longer holds for mixed *** contribute to a better understanding of this differentiation,we have explored a simple model for both generating and measuring these quantum *** study concerns two macroscopic mechanical resonators placed in separate Fabry–Pérot cavities,coupled through the photon hopping *** system offers a comprehensively way to investigate and quantify quantum correlations beyond entanglement between these mechanical *** key ingredient in analyzing quantum correlation in this system is the global covariance *** forms the basis for computing two essential metrics:the logarithmic negativity(E_(N)^(m))and the Gaussian interferometric power(P_(G)^(m)).These metrics provide the tools to measure the degree of quantum entanglement and quantum correlations,*** study reveals that the Gaussian interferometric power(P_(G)^(m))proves to be a more suitable metric for characterizing quantum correlations among the mechanical modes in an optomechanical quantum system,particularly in scenarios featuring resilient photon hopping.

关键词： quantum correlations entanglement Gaussian interferometric power logarithmic negativity optomechanics photon hopping

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The great catastrophe: causes of the Permo-Triassic marine mass extinction

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National Science Review 2024年第1期11卷 37-50页

作者： Paul b.Wignall David P.G.bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South china, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(cades) and the overwhelming evidence for rapid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

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Academic productivity correlates with industry earnings in foot and ankle fellowship programs in the United States:A retrospective analysis

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World Journal of Orthopedics 2024年第2期15卷 129-138页

作者： Albert T Anastasio Anthony N baumann Kempland c Walley Kyle J Hitchman conor O’Neill Jonathan Kaplan Samuel b Adams Department of Orthopedic Surgery Duke University HospitalDurhamNC 27710United States college of Medicine Northeast Ohio Medical UniversityRootstownOH 44272United States Department of Orthopedic Surgery University of MichiganAnn ArborMI 48109United States School of Osteopathic Medicine Campbell UniversityLillingtonNC 27546United States

bAcKGROUND The study investigates the connection between academic productivity and industry earnings in foot and ankle orthopedic surgery *** metrics like the H-index and Open Payments Database(OPD)data,it addresses a gap in understanding the relationship between scholarly achievements and financial outcomes,providing a basis for further exploration in this specialized medical *** To elucidate the trends between academic productivity and industry earnings across foot and ankle orthopedic surgery fellowship programs in the United *** This study is a retrospective analysis of the relationship between academic productivity and industry earnings of foot and ankle orthopedic surgery fellowships at an individual faculty and fellowship *** productivity was defined via H-index and recorded from the Scopus *** earnings were recorded from the *** Forty-eight foot and ankle orthopedic surgery fellowships(100%of fellowships)in the United States with a combined total of 165 physicians(95.9%of physicians)were *** individual physician(n=165)total life-time earnings reported on the OPD website was United States Dollar(USD)451430.30±1851084.89(range:USD 25.16-21269249.85;median:USD 27839.80).Mean physician(n=165)H-index as reported on Scopus is 14.24±12.39(range:0-63;median:11).There was a significant but weak correlation between individual physician H-index and individual physician total life-time earnings(Pcant and moderate positive correlation between combined fellowship H-index and total life-time earnings per fellowship(P=0.004,Spearman’s rho=0.409).cONcLUSION There is a significant and positive correlation between academic productivity and industry earnings at foot and ankle orthopedic surgery fellowships in the United *** observation is true on an individual physician level as well as on a fellowship level.

关键词： Sunshine act Foot and ankle Orthopedic surgery Orthopedic fellowship Industry earnings

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A Hybrid Machine Learning Approach for Improvised QoE in Video Services over 5G Wireless Networks

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computers, Materials & continua 2024年第3期78卷 3195-3213页

作者： K.b.Ajeyprasaath P.Vetrivelan School of Electronics Engineering Vellore Institute of TechnologyChennaiTamil Nadu600127India

Video streaming applications have grown considerably in recent *** a result,this becomes one of the most significant contributors to global internet *** to recent studies,the telecommunications industry loses millions of dollars due to poor video Quality of Experience(QoE)for *** the standard proposals for standardizing the quality of video streaming over internet service providers(ISPs)is the Mean Opinion Score(MOS).However,the accurate finding of QoE by MOS is subjective and laborious,and it varies depending on the user.A fully automated data analytics framework is required to reduce the inter-operator variability characteristic in QoE *** work addresses this concern by suggesting a novel hybrid XGbStackQoE analytical model using a two-level layering *** one combines multiple Machine Learning(ML)models via a layer one Hybrid *** ML models at level one are trained using the entire training data *** level two Hybrid XGbStackQoE-Model is fitted using the outputs(meta-features)of the layer one ML *** proposed model outperformed the conventional models,with an accuracy improvement of 4 to 5 percent,which is still higher than the current traditional *** proposed framework could significantly improve video QoE accuracy.

关键词： Hybrid XGbStackQoE-model machine learning MOS performance metrics QoE 5G video services

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