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关键词： amphibian   clutch quality   early life   embryonic development   hatching success   reproductive success  

摘要： Reproductive success is often related to parental quality, a parameter expressed through various traits, such as site selection, mate selection and energetic investment in the eggs or progeny. Owing to the complex interactions between environmental and parental characteristics occurring at various stages of the reproductive event, it is often complicated to tease apart the relative contributions of these different factors to reproductive success. Study systems where these complex interactions are simplified (e.g. absence of parental care) can help us to understand how metrics of parental quality (e.g. gamete and egg quality) influence reproductive success. Using such a study system in a common garden experiment, we investigated the relationships between clutch hatching success (a proxy of clutch quality) and offspring quality in an amphibian species lacking post-oviposition parental care. We found a relationship between clutch quality and embryonic development duration and hatchling phenotype. We found that hatchling telomere length was linked to hatching success. These results suggest that clutch quality is linked to early life traits in larval amphibians and that deciphering the influence of parental traits on the patterns we detected is a promising avenue of research.

关键词： Bamboo structures   Full-culm bamboo   Round bamboo   Bolted connection   Dowel-type connection   Capacity design   Managing variability  

摘要： This study presents a first attempt toward the rational design of bamboo multiculm axial members with dowel-type connections. Specifically, it implements an original combination of grading, use of multiple culms, and capacity design principles to manage the natural variability of bamboo culms and establish a reliable ductile failure. In this context, the study also calibrates the pertinent overstrength factors needed for achieving capacity-based design. The proposed axial members display high ductility and predictability owing to dowel yielding before the other components, i.e., the steel gusset plates and the bamboo culms fail. Furthermore, arranging bolts along two perpendicular planes of the circular cross-section of bamboo culms increases efficiency and offers notable gains in strength over a single plane bolt configuration. The characteristic values of average material/geometric properties of multiculm members estimated from single-culm material tests can predict the experimental 5th percentile yielding of dowel connections with accuracy. Overall, the proposed approach results in reliable multiculm bamboo axial members and shows promise toward a rational engineered design of bamboo structures.

摘要： Caseinolytic mitochondrial matrix peptidase proteolytic subunit (CLPP) is a serine protease that degrades damaged or misfolded mitochondrial proteins. CLPP-null mice exhibit growth retardation, deafness, and sterility, resembling human Perrault syndrome, but also display immune system alterations. However, the molecular mechanisms and signaling pathways underlying immunological changes in CLPP-null mice remain unclear. In this study, we report the steady-state activation of type I IFN signaling and antiviral gene expression in CLPP-deficient cells and tissues, resulting in marked resistance to RNA and DNAvirus infection. Depletion of the cyclic GMP-AMP (cGAS)-stimulator of IFN genes (STING) DNA sensing pathway reduces steady-state IFN-I signaling and abrogates the broad antiviral phenotype of CLPP-null cells. Moreover, we report that CLPP deficiency leads to mitochondrial DNA (mtDNA) instability and packaging alterations. Pharmacological and genetic approaches to deplete mtDNA or inhibit cytosolic release markedly reduce antiviral gene expression, implicating mtDNA stress as the driver of IFN-I signaling in CLPP-null mice. Our work places the cGAS-STING-IFN-I innate immune pathway downstream of CLPP and may have implications for understanding Perrault syndrome and other human diseases involving CLPP dysregulation.

摘要： This case study examined the effects of a clutch-based hypnotic intervention on the performance and experience of a senior PGA tour golfer. The intervention encompassed hypnosis, regression imagery, a trigger control technique, and a preshot routine. Golf performance data were analyzed using a single-subject design. The results indicated that the player's mean stroke average decreased from baseline to postintervention. The qualitative data suggests that the hypnotic intervention may help golfers regulate emotions, thoughts, feelings, and perceptions associated with a clutch state experience.

关键词： 车辆   离合器   接合过程   滑摩状态   动力模型   评价指标  

摘要： 离合器是汽车传动系统的重要组成部分,其接合过程直接影响到车辆起步性能和动力传递,并影响系统各单元的使用寿命。针对离合器接合过程的特点,对滑摩状态和接合状态进行动力学分析,建立系统的动力学模型;从滑摩功和冲击度两个方面对离合器接合过程进行评价,获取影响换挡品质的评价指标因素;根据动力模型和数学模型,基于Simulink建立离合器接合过程的分析模型;研究不同坡度及载重等因素对离合器接合过程中摩擦片的角速度、滑摩功及冲击度的影响,获取各因素的影响规律。结果可知:随着油门开度和油门变化率的逐渐增大,离合器接合角速度和接合时间都有所增大,接合过程产生的滑摩功也不断增多;随着起步坡度、载重的增大,离合器接合角速度逐渐减小,接合时间逐渐增大,接合过程产生的滑摩功也不断增多;分析过程和结果为此类设计提供参考。

关键词： 双离合变速器   双离合器   换挡冲击   行驶里程   机电控制   异响   传动效率   售后维修  

摘要： 近年来,凭借传动效率高、换挡速度快、驾驶体验好、使用油耗低等诸多优点,双离合变速器发展势头迅猛,搭载双离合变速器的车辆越来越多。随着车辆使用年限和行驶里程的增加,双离合变速器售后维修市场潜力巨大。常见的双离合变速器故障有换挡异响、换挡冲击、无法换挡等,其主要原因为双离合器故障和机电控制单元故障。

关键词： 离合器飞轮   楔形块补贴   缩松   补缩通道   动平衡  

摘要： 通过在模具上(铸件的相应位置)增加一楔形块,人为地加大补缩通道,实现冒口颈与铸件缩松部位的桥接,保持补缩通道一直通畅,从而实现通过这个楔形块(加上原有铸件厚度)顺畅地将冒口中的金属液直接补充到需要补缩的部位。

关键词： 湿式离合器   传递扭矩   窜油   汽车制造企业   占用空间   液压控制系统   压力机   问题分析与解决  

摘要： 在当前的各大汽车制造企业中,配备湿式离合器的大型机械压力机被广泛应用,湿式离合器具有控制精准、离合/制动响应速度快、传递扭矩大,且占用空间小、无粉尘及动作噪声小等特点,能够很好地满足压力机对离合器传动及控制的要求但与此同时湿式离合器也存在一些缺点,如液压控制系统较复杂,故障判断及解决较困难,尤其是窜油问题,是湿式离合器在使用过程中的一个痛点,一个困扰设备团队的老大难问题。

关键词： 玉米收获机   离合器   结构  

摘要： 从结构和工作原理方面对玉米收获机两种常用主传动离合器进行了介绍和对比分析,依据分析结论提出了相关选用建议。

关键词： 离合器   干扰   车辆整体  

摘要： 通过两例发动机转速异常表现故障的分析、处理,指出离合器对动力传输的影响,以及对发动机转速信号的干扰问题。在解决发动机转速问题时,需要从车辆整体考虑,不能因发动机问题而将思维限制在发动机上。