Dynamic model

动态模型
  • 文章类型: Journal Article
    甲型流感有两个血凝素组,与群体之间相比,内部对再感染的交叉免疫力更强。这里,我们探讨了这种异质性对拟议的交叉保护性流感疫苗的影响,这些疫苗可能提供广泛的,但不是普遍的,保护。虽然人类甲型流感疫苗的开发目标是提供跨群体保护,目前发展阶段的疫苗可能比非目标群体对目标群体提供更好的保护。为了评估疫苗配方和策略,我们提出了一个新的观点:疫苗群体水平目标产品概况(PTPP)。在这个视角下,我们使用动态模型来量化未来甲型流感疫苗的流行病学影响,作为其特性的函数.我们的结果表明,天然免疫和疫苗诱导免疫的相互作用可以强烈影响季节性亚型动态。广泛保护性的二价疫苗可以降低两组的发病率,并以足够的疫苗接种覆盖率实现消除。然而,低疫苗接种率的单价疫苗可以允许非目标人群在疫苗提供比自然感染更弱的免疫力时复活。此外,作为大流行模拟的代理,我们分析了一种逃避自然免疫的变种的入侵。我们发现,未来的疫苗在足够高的疫苗接种率下提供足够广泛和长寿命的跨群体保护,可以防止大流行的出现并减轻大流行的负担。这项研究强调,除了有效性之外,对于未来的人类甲型流感疫苗,应在流行病学知情的TPPs中考虑宽度和持续时间。
    Influenza A has two hemagglutinin groups, with stronger cross-immunity to reinfection within than between groups. Here, we explore the implications of this heterogeneity for proposed cross-protective influenza vaccines that may offer broad, but not universal, protection. While the development goal for the breadth of human influenza A vaccine is to provide cross-group protection, vaccines in current development stages may provide better protection against target groups than non-target groups. To evaluate vaccine formulation and strategies, we propose a novel perspective: a vaccine population-level target product profile (PTPP). Under this perspective, we use dynamical models to quantify the epidemiological impacts of future influenza A vaccines as a function of their properties. Our results show that the interplay of natural and vaccine-induced immunity could strongly affect seasonal subtype dynamics. A broadly protective bivalent vaccine could lower the incidence of both groups and achieve elimination with sufficient vaccination coverage. However, a univalent vaccine at low vaccination rates could permit a resurgence of the non-target group when the vaccine provides weaker immunity than natural infection. Moreover, as a proxy for pandemic simulation, we analyze the invasion of a variant that evades natural immunity. We find that a future vaccine providing sufficiently broad and long-lived cross-group protection at a sufficiently high vaccination rate, could prevent pandemic emergence and lower the pandemic burden. This study highlights that as well as effectiveness, breadth and duration should be considered in epidemiologically informed TPPs for future human influenza A vaccines.
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  • 文章类型: Journal Article
    背景:在法国,流感占与全科医生的平均咨询次数超过一百万次,两万人住院,每年有9000人死亡,尤其是在65岁以上的人群中。这项研究评估了法国65岁及以上人群的佐剂四价流感疫苗(aQIV)与标准(SD-QIV)和高剂量(HD-QIV)四价流感疫苗的成本效益。
    方法:年龄结构化的SEIR传输模型,校准以模拟平均流感季节,结合了一个联系矩阵来估计组间联系率。流行病学,经济,并评估效用结果。疫苗有效性和成本来自文献和国家保险数据。应用流感发作率和住院率的生活质量调整。还进行了确定性和概率分析。
    结果:与SD-QIV相比,aQIV表明医疗保健利用率和死亡率大幅下降,避免89,485名GP咨询,2144例住院,防止1611人死亡。尽管投资了1.1亿欧元,aQIV产生净节省1400万欧元的医疗保健支出。与HD-QIV相比,aQIV节省了6200万欧元的疫苗接种费用。成本效益分析显示,每QALY的增量成本效益比为7062欧元。
    结论:本研究强调了aQIV与SD-QIV和HD-QIV的成本效益,预防流感病例,住院治疗,和死亡。
    BACKGROUND: In France, influenza accounts for an average of over one million consultations with GPs, 20,000 hospitalizations, and 9000 deaths per year, particularly among the over-65s. This study evaluates the cost-effectiveness of the adjuvanted quadrivalent influenza vaccine (aQIV) compared to standard (SD-QIV) and high-dose (HD-QIV) quadrivalent influenza vaccines for individuals aged 65 and older in France.
    METHODS: The age-structured SEIR transmission model, calibrated to simulate a mean influenza season, incorporates a contact matrix to estimate intergroup contact rates. Epidemiological, economic, and utility outcomes are evaluated. Vaccine effectiveness and costs are derived from literature and national insurance data. Quality of life adjustments for influenza attack rates and hospitalizations are applied. Deterministic and probabilistic analyses are also conducted.
    RESULTS: Compared to SD-QIV, aQIV demonstrates substantial reductions in healthcare utilization and mortality, avoiding 89,485 GP consultations, 2144 hospitalizations, and preventing 1611 deaths. Despite an investment of EUR 110 million, aQIV yields a net saving of EUR 14 million in healthcare spending. Compared to HD-QIV, aQIV saves 62 million euros on vaccination costs. Cost-effectiveness analysis reveals an incremental cost-effectiveness ratio of EUR 7062 per QALY.
    CONCLUSIONS: This study highlights the cost-effectiveness of aQIV versus SD-QIV and HD-QIV, preventing influenza cases, hospitalizations, and deaths.
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  • 文章类型: Journal Article
    明确石油烃在土壤中的赋存状态和形态特征,有助于全面了解石油烃在土壤/沉积物中的迁移和转化规律。此外,通过建立每个发生状态的动态转换过程,可以更准确地评估与土壤/沉积物中PHs相关的生态影响和环境风险。通过基于Tenax-TA的新型顺序提取方法,进行了吸附实验和封闭静态孵育实验,以探索外源细菌自然衰减(NA)和生物强化(BA)两种修复方案下老化污染土壤中PHs的降解和分数分布。羟丙基-β-环糊精和鼠李糖脂(HPCD/RL),加速溶剂萃取器(ASE)装置和碱水解萃取。吸附实验结果表明,生物强化可以促进PHs在吸附阶段的解吸,土水分配系数Kd由0.153L/g降至0.092L/g。孵化实验结果表明,与自然衰减相比,生物强化可以提高老化土壤中PHs的利用率,促进不可提取烃的产生。在实验的第90天,自然衰减和生物强化实验组的弱吸附烃浓度分别下降了46.44%和87.07%,分别,强吸附烃和不可萃取烃的浓度增加了77.93%,182.14%,80.91%,和501.19%,分别,比较它们的初始值。我们开发了一个新的动力学模型,并通过参数扫描函数和基于COMSOLMultiphysics®有限元软件中的贝叶斯方法结合实验数据的马尔可夫链蒙特卡罗(MCMC)方法反演了模型的动力学参数。实验插值数据与模型预测数据之间存在良好的线性关系。弱吸附烃浓度的R2为0.9953至0.9974,强吸附烃的R2为0.9063至0.9756,不可萃取烃的R2为0.9931至0.9982。这些极高的相关系数证明了使用贝叶斯反演方法计算的参数的高精度。
    Clarifying the occurrence and morphological characteristics of petroleum hydrocarbons (PHs) in soil can facilitate a comprehensive understanding of their migration and transformation patterns in soil/sediment. Additionally, by establishing the dynamic transformation process of each occurrence state, the ecological impact and environmental risk associated with PHs in soil/sediment can be assessed more precisely. The adsorption experiments and closed static incubation experiments was carried out to explore the PHs degradation and fraction distribution in aged contaminated soil under two remediation scenarios of natural attenuation (NA) and bioaugmentation (BA) by exogenous bacteria through a new sequential extraction method based on Tenax-TA, Hydroxypropyl-β-cyclodextrin and Rhamnolipid (HPCD/RL), accelerated solvent extractor (ASE) unit and alkaline hydrolysis extraction. The adsorption experiment results illustrated that bioaugmentation could promote the desorption of PHs in the adsorption phase, and the soil-water partition coefficient Kd decreased from 0.153 L/g to 0.092 L/g. The incubation experiment results showed that compared with natural attenuation, bioaugmentation could improve the utilization of PHs in aged soil and promote the generation of non-extractable hydrocarbons. On the 90th day of the experiment, the concentrations of weakly adsorbed hydrocarbons in the natural attenuation and bioaugmentation experimental groups decreased by 46.44% and 87.07%, respectively, while the concentrations of strongly adsorbed hydrocarbons and non-extractable hydrocarbons increased by 77.93%, 182.14%, and 80.91%, and 501.19%, respectively, compared their initial values. We developed a novel dynamic model and inverted the kinetic parameters of the model by the parameter scanning function and the Markov Chain Monte Carlo (MCMC) method based on the Bayesian approach in COMSOL Multiphysics® finite element software combined with experimental data. There was a good linear relationship between experimental interpolation data and model prediction data. The R2 for the concentrations of weakly adsorbed hydrocarbons ranged from 0.9953 to 0.9974, for strongly adsorbed hydrocarbons from 0.9063 to 0.9756, and for non-extractable hydrocarbons from 0.9931 to 0.9982. These extremely high correlation coefficients demonstrate the high accuracy of the parameters calculated using the Bayesian inversion method.
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  • 文章类型: Journal Article
    在卫生和雨水下水道系统中,通风对于减轻气味问题和避免压力波动至关重要。由于气流建模不足或仅适用于稳态条件,现有的数值模型在实际下水道系统中的实际应用中受到限制。这项研究努力制定一个数学模型,能够准确地模拟自然通风条件下下水道系统的各种运行条件。使用冲击捕获MacCormack方案对动态水流进行建模。动态气流模型融合了能量和动量方程,规避费力的压力迭代计算。该模型利用界面处的摩擦系数来增强对气流中动量交换的描述,并为气压提供逻辑解释。系统分析表明,该模型可以很容易地适应复杂的边界条件,便于将其用于真实下水道网络中的气流建模。此外,这项研究揭示了在自然通风条件下,空气与水流量比与填充比之间的直接相关性,并推导出了包含这种关系的经验公式。这一发现为实际工程应用提供了见解。
    Ventilation is paramount in sanitary and stormwater sewer systems to mitigate odor problems and avert pressure surges. Existing numerical models have constraints in practical applications in actual sewer systems due to insufficient airflow modeling or suitability only for steady-state conditions. This research endeavors to formulate a mathematical model capable of accurately simulating various operational conditions of sewer systems under the natural ventilation condition. The dynamic water flow is modeled using a shock-capturing MacCormack scheme. The dynamic airflow model amalgamates energy and momentum equations, circumventing laborious pressure iteration computations. This model utilizes friction coefficients at interfaces to enhance the description of the momentum exchange in the airflow and provide a logical explanation for air pressure. A systematic analysis indicates that this model can be easily adapted to include complex boundary conditions, facilitating its use for modeling airflow in real sewer networks. Furthermore, this research uncovers a direct correlation between the air-to-water flow rate ratio and the filling ratio under natural ventilation conditions, and an empirical formula encapsulating this relationship is derived. This finding offers insights for practical engineering applications.
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  • 文章类型: Journal Article
    小尺寸的属性,低噪音,高性能和无磨损使半球形谐振陀螺仪成为高价值太空任务的好选择。为了提高半球形谐振陀螺仪在具有大角速度和角加速度的任务中使用的精度,本文研究了非线性高强度动态条件下非理想半球形谐振器的驻波进动。基于薄壳弹性理论,利用拉格朗日第二类方程建立了半球形谐振器的动力学模型。然后,将动力学模型等效转换为二维空间中的点质量的简谐振动模型,这是使用一种将慢速变量与快速变量分开的平均方法进行分析的。结果表明,考虑到动力学方程中关于角速度平方和角加速度的非线性项,可以减弱质量缺陷的4次谐波分量对驻波漂移的影响。这种弱化效应的程度随质量缺陷的大小而变化,这对于指导高精度半球形谐振陀螺的发展具有十分重要的意义。
    The properties of small size, low noise, high performance and no wear-out have made the hemispherical resonator gyroscope a good choice for high-value space missions. To enhance the precision of the hemispherical resonator gyroscope for use in tasks with large angular velocities and angular accelerations, this paper investigates the standing wave precession of a non-ideal hemispherical resonator under nonlinear high-intensity dynamic conditions. Based on the thin shell theory of elasticity, a dynamic model of a hemispherical resonator is established by using Lagrange\'s second kind equation. Then, the dynamic model is equivalently transformed into a simple harmonic vibration model of a point mass in two-dimensional space, which is analyzed using a method of averaging that separates the slow variables from the fast variables. The results reveal that taking the nonlinear terms about the square of the angular velocity and the angular acceleration in the dynamic equation into account can weaken the influence of the 4th harmonic component of a mass defect on standing wave drift, and the extent of this weakening effect varies with the dimensions of the mass defects, which is very important for steering the development of the high-precision hemispherical resonator gyroscope.
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  • 文章类型: Journal Article
    日本李子,像其他温带果树一样,在休眠期间具有特定品种的温度要求,以实现适当的开花。由于可用的日本李子型品种之间存在巨大的遗传变异性,因此知道该物种的温度要求越来越受到人们的关注,因为它们大多数是种间杂种。气候变化导致的冬季寒冷减少正在威胁许多地区的种植。在这项工作中,在西班牙两个主要的李子种植区分析了21个日本李子型品种的适应前景,巴达霍斯和萨拉戈萨,未来的气候条件。通过在至少两年的休眠期间进行的经验实验,确定了内部休眠释放,以用于随后估计的冷却和热量需求。使用三种模型计算冷却需求[冷却小时(CH),冷却单元(CU)和冷却部分(CP)]和热量要求使用增长的小时数(GDH)。冷却要求范围为277-851CH,412-1,030CU和26-51CP,热量需求范围从4,343到9,525GDH。在两个代表性浓度路径(RCP)下,使用气候预测评估了品种对两个地区未来温暖条件的潜在适应,RCP4.5(有效减少温室气体排放)和RCP8.5(持续增加温室气体排放),在两个时间范围内,从21世纪中叶到21世纪末,来自15个全球气候模型的温度预测。在巴达霍斯,满足估计的特定品种冷藏需求的可能性低于萨拉戈萨,因为预测的寒冷可用性较低。在这个地区,例如,本文分析的品种可能具有有限的栽培,因为预测的冬季寒冷的减少可能导致不能成功地满足冷藏要求。
    Japanese plum, like other temperate fruit tree species, has cultivar-specific temperature requirements during dormancy for proper flowering. Knowing the temperature requirements of this species is of increasing interest due to the great genetic variability that exists among the available Japanese plum-type cultivars, since most of them are interspecific hybrids. The reduction of winter chilling caused by climate change is threatening their cultivation in many regions. In this work, the adaptation perspectives of 21 Japanese plum-type cultivars were analyzed in two of the main plum-growing regions in Spain, Badajoz and Zaragoza, to future climate conditions. Endodormancy release for subsequent estimation of chilling and heat requirements was determined through empirical experiments conducted during dormancy at least over two years. Chill requirements were calculated using three models [chilling hours (CH), chilling units (CU) and chilling portions (CP)] and heat requirements using growing degree hours (GDH). Chilling requirements ranged 277-851 CH, 412-1,030 CU and 26-51 CP, and heat requirements ranged from 4,343 to 9,525 GDH. The potential adaption of the cultivars to future warmer conditions in both regions was assessed using climate projections under two Representative Concentration Pathways (RCP), RCP4.5 (effective reduction of greenhouse gas emissions) and RCP8.5 (continuous increase in greenhouse gas emissions), in two time horizons, from the middle to the end of 21st century, with temperature projections from 15 Global Climate Models. The probability of satisfying the estimated cultivar-specific chilling requirements in Badajoz was lower than in Zaragoza, because of the lower chill availability predicted. In this region, the cultivars analyzed herein may have limited cultivation because the predicted reduction in winter chill may result in the chilling requirements not being successfully fulfilled.
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  • 文章类型: English Abstract
    为了准确预测用电动重型柴油卡车取代重型柴油卡车的生命周期碳减排效益,以一辆重型卡车为对象,分阶段建立了重型卡车的动态碳排放模型。在“2050年净零排放情景(NZE)”下,卡车的碳足迹“宣布承诺方案(APS)”,和“既定政策方案(步骤)”进行了分析。此外,计算了碳还原率和碳还原率。结果表明,电池制造和电池回收是影响电动重型卡车生产和回收阶段碳减排改善的主要因素,分别。电碳排放因子(CO2)每降低1g·(kW·h)-1,一辆电动重型卡车在其生命周期内可以减少1.74吨的碳排放量。在这三种情况下,两种重型卡车在运营阶段的碳排放量占整个生命周期碳排放量的90%以上。从最高到最低的碳减排效益是NZE,APS,和步骤,其对应的生命周期碳减排量分别为1054.68、1021.78和1007.97t,碳减排率为54.38%,52.68%,和51.97%,分别。
    To accurately predict the life-cycle carbon reduction benefits of replacing a diesel heavy-duty truck with an electric one, taking a single heavy-duty truck as the object, the variation trend in electric and diesel carbon emission factors from 2023 to 2050 were predicted; coupled with the life spans and life-cycle mileage of the two types of heavy-duty trucks, a dynamic carbon emission model for the heavy-duty trucks was constructed in stages. The carbon footprints of the trucks under the \"Net Zero Emissions by 2050 Scenario (NZE)\", \"Announced Pledges Scenario (APS)\", and \"Stated Policies Scenario (STEPS)\" were analyzed. In addition, the carbon reduction and carbon reduction rate were calculated. The results showed that battery manufacturing and battery recycling were the main factors to impair the improvement of carbon reduction in the production and recycling stages of electric heavy-duty trucks, respectively. For every 1 g·(kW·h)-1 reduction in the electricity carbon emission factor (CO2), an electric heavy-duty truck could reduce 1.74 t of carbon emissions over its life cycle. Under the three scenarios, the carbon emissions during the operation stage of both types of heavy trucks accounted for more than 90% of the total life-cycle carbon emissions. Carbon reduction benefits from the highest to the lowest were NZE, APS, and STEPS, and their corresponding life-cycle carbon emission reductions were 1054.68, 1021.78, and 1007.97 t, with carbon reduction rates of 54.38%, 52.68%, and 51.97%, respectively.
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  • 文章类型: Journal Article
    休眠现象及其发展的进化原因以及气候因素的影响:温度和光照。已发现阴影和黑暗可以增强桃子中的芽破裂。各种温度对冷却积累的影响,描述了冷却的否定和冷却的增强。解释了面对全球变暖时计算这些的方式,使用动态模型。当自然冷却小于要求时,有补偿的方法,到一定程度。各种园艺,描述了实现这一目标的物理和化学手段,包括弯曲的树枝,减少植物人的活力,遮蔽果园,洒水以降低白天的温度,并应用各种化学物质来打破休眠。当冬季寒冷显着减少并且温度大大增加时,建议在无霜的地方使用避免休眠。这种技术可以通过完全避免休眠来诱导新的生长周期。然而,最好的方法是培育高质量的品种,需要少得多的冷却。在这项工作中讨论的另一个方面,独立于冷却要求,是冬季和春季的热法术对花蕾异常发育的负面影响,导致核果组水平低,产量下降。
    The phenomenon of dormancy and the evolutionary causes for its development are presented together with the effects of the climatic factors: temperature and light. Shade and darkness have been found to enhance bud breaking in peach. The effects of various temperatures on chilling accumulation, chilling negation and chilling enhancement are described. The way these are computed in the face of global warming is explained, using the dynamic model. When natural chilling is less than that required, there are ways of compensation, up to a certain level. Various horticultural, physical and chemical means to achieve this are described, including bending branches, reducing vegetative vigor, shading the orchard, sprinkling to reduce daytime temperature and the application of various chemicals to break dormancy. When winter chilling is markedly reduced and temperatures increase considerably, the use of dormancy avoidance is suggested in frost-free places. This technique can induce a new growing cycle by avoiding dormancy altogether. However, the best approach is to breed high-quality cultivars requiring much less chilling. Another aspect discussed in this work, independent of the chilling requirement, is the negative effect of heat spells in winter and spring on the abnormal development of flower buds, leading to a low level of the stone fruit set and a reduced yield.
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  • 文章类型: Journal Article
    扭转振动是转子动力学中的一个重要现象。它由轴的振荡运动组成,并导致多个振荡应用领域的故障。这种类型的振动比横向振动更难测量。扭转振动计通常是侵入性的,需要复杂的设置,以及不便于现场测量。最可靠的,非侵入性,可移动测量技术涉及激光扭转振动计。对于这项研究,使用了两个具有不同测量能力的激光头。实验测试装置用于执行两个激光振动计的相对校准。作用力的频率和轴的转速在同一范围内变化,这是常见的旋转机器。最后,使用激光振动计的扭转振动的实验测量值与同一试验台的一维有限元模型的数值结果进行了比较。本文的主要成果是定义了一种可靠的测量程序,以利用两个激光振动计来检测真实机器上的扭转模态和固有频率。详细描述了两种不同测量头的相对校准,该程序是正确关联两个机器部分中的测量信号的基础。发现了数值结果与实验结果之间的良好对应关系。
    Torsional vibration is a critical phenomenon in rotor dynamics. It consists of an oscillating movement of the shaft and causes failures in multiple oscillating fields of application. This type of vibration is more difficult to measure than lateral vibration. Torsional vibrometers are generally invasive and require a complicated setup, as well as being inconvenient for field measurements. One of the most reliable, non-invasive, and transportable measuring techniques involves the laser torsional vibrometer. For this research, two laser heads with different measurement capabilities were utilized. An experimental test rig was used to perform a relative calibration of the two laser vibrometers. The frequency of the acting force and the rotation speed of the shaft vary in the same range, which is commonly found in rotating machines. Finally, experimental measurements of torsional vibrations using laser vibrometers were compared with numerical results from a 1D finite element model of the same test rig. The main outcome of this paper is the definition of a reliable measuring procedure to exploit two laser vibrometers for detecting torsional mode-shapes and natural frequencies on real machines. The relative calibration of two different measuring heads is described in detail, and the procedure was fundamental to properly correlate measuring signals in two machine sections. A good correspondence between the numerical and experimental results was found.
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  • 文章类型: Journal Article
    近年来,国内外对四足机器人的研究都朝着高动态性和敏捷性发展,重点是高速运动作为高动态活动中的代表运动。像猎豹这样的四足动物表现出高速运行的能力,归因于在飞行阶段运动过程中它们的柔性脊柱所发挥的不可或缺的作用。本文建立了不同简化程度的柔性脊柱四足机器人的动力学模型,提供刚性躯干和柔性脊柱四足机器人飞行阶段运动的参数化描述。通过为脊柱关节设置不同的初始值,并计算两种类型机器人在不同初始速度下的飞行阶段结果,这项研究比较和分析了柔性脊柱对四足机器人飞行阶段运动的影响。通过对比实验,该研究旨在验证在飞行阶段运动过程中柔性脊柱的影响,提供有关脊柱灵活性如何影响四足机器人飞行阶段运动的见解。
    In recent years, both domestic and international research on quadruped robots has advanced towards high dynamics and agility, with a focus on high-speed locomotion as a representative motion in high-dynamic activities. Quadruped animals like cheetahs exhibit high-speed running capabilities, attributed to the indispensable role played by their flexible spines during the flight phase motion. This paper establishes dynamic models of flexible spinal quadruped robots with different degrees of simplification, providing a parameterized description of the flight phase motion for both rigid-trunk and flexible-spine quadruped robots. By setting different initial values for the spine joint and calculating the flight phase results for both types of robots at various initial velocities, the study compares and analyzes the impact of a flexible spine on the flight phase motion of quadruped robots. Through comparative experiments, the research aims to validate the influence of a flexible spine during the flight phase motion, providing insights into how spine flexibility affects the flight phase motion of quadruped robots.
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