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To study the probabilistic distribution of maximum wheel unloading rate of high-speed trains and its temporal correlation when a train passes over a bridge, a method for the estimation of the extremal index is proposed. Using the time series threshold theory, the maximum value cumulative distribution function (CDF) when the wheel unloading rate is regarded as a time series is derived and validated. This approach can also address dependent series, which the traditional probability distribution function formulas could not. Then, the difference between treating the wheel unloading rate as a time series and independent series is investigated using Monte Carlo simulations. Finally, the influence of the number of calculation steps on the threshold is studied, and the differences between thresholds calculated by different extremal indices when considering the number of trains running during the service period of the bridge are explored. The maximum value CDFs of the wheel unloading rate for different track irregularities, bridge lengths, and vehicle speeds are investigated for a three-span simply-supported bridge. The results show that the differences in the maximum value probability density functions (PDFs) obtained by considering the wheel unloading rate as time series and independent random series cannot be ignored. However, when studying a high-confidence level problem, such as the threshold of the wheel unloading rate, the difference between the two approaches is small enough. As the number of calculation steps increases, the extremal index will gradually decrease. When considering a long-distance high-speed rail line, its shorter segment can be used to study the threshold of the wheel unloading rate. [ABSTRACT FROM AUTHOR]

Personnel management practices affect the success of joint ventures. In the international arena, human resource practices are even more crucial in facilitating the cooperation of personnel from different cultures. Chinese-Japanese joint ventures, wherein human resource utilization was found to be higher than those in other regions, provide a fertile ground for examining the personnel management dynamics and patterns existing among different firms with foreign partners of the same nationality. The results of ten case studies are provided.

Feng Shui woodlands are naturally or artificially formed green areas in southern China. They are precious for maintaining ecosystem balance in modern semiurban environments. However, they are generally small and geographically isolated from each other, and the status of genetic diversity of the plant species within them has been almost neglected. Therefore, we studied the genetic diversity of the endangered Erythrophleum fordii in eight Feng Shui woodlands (a total of 1,061 individuals) in Guangzhou, a large city in southern China, using microsatellites. For comparison, one population with 33 individuals sampled in a nature reserve was also studied. Although our results indicate that significant demographic declines occurred historically in E. fordii, such declines have not resulted in consistent reductions in genetic variation over generations in Feng Shui populations in the recent past, and the levels of genetic variation in these populations were higher than or comparable to the genetic variation of the population in the nature reserve. In addition, our parentage and paternity analyses indicated widespread and potential long‐distance pollen flow within one Feng Shui woodland, indicating the presence of an unbroken pollination network, which would at least partially alleviate the genetic erosion due to habitat fragmentation and the unequal gene contributions of E. fordii parents to their progenies when favorable recruitment habitats are absent under most of the parent trees. Overall, our results suggest that E. fordii in Feng Shui woodlands may not be driven to extinction in the near future. Nevertheless, uncontrolled fast urban development with a lack of awareness of Feng Shui woodlands will cause the local extinction of E. fordii, which has already happened in some Feng Shui woodlands. [ABSTRACT FROM AUTHOR]

Temperatures are expected to fluctuate widely under climate change but little is known about how extreme temperatures might affect the physiology and performance of invasive compared to native plant species. In this study, we evaluated the effects of high (40/35°C) and low (10/5°C) temperature regimes on the growth and photosynthesis of the invasive Asteraceae species Bidens alba and its native congener B. biternata using a growth chamber experiment. Results showed that invasive B. alba had significantly greater total biomass and relative growth rate, accompanied by higher net photosynthetic rate (Pn), than native B. biternata at both low and high temperature extremes. The reduction in Pn for B. alba was mainly caused by stomatal limitations, but for B. biternata it was caused by non-stomatal factors, indicating that greater damage to physiological processes may occur in native B. biternata under both low and high temperature stress. Higher cyclic electron flow around photosystem I in invasive B. alba than in native B. biternata under extreme temperatures might alleviate the negative effect of temperature extremes to photosynthetic and thus promote its photosynthetic efficiency. To conclude, the invasive B. alba has both greater cold and heat tolerance than its native congener B. biternata, suggesting that the invader may outperform native species under future extreme temperature conditions. [ABSTRACT FROM AUTHOR]

Biological invasion is a global environmental issue. Hybridization is considered a stimulus for evolution of invasiveness. It is thus essential to evaluate the invasive potential of new hybrids before management strategies are designed and implemented for them, especially, using performance-related traits. Comparing growth and physiological traits between invasive species and their non-invasive congeners is an effective way to identify invasive traits and to predict the invasive potential of species. However, few studies have evaluated the invasive potential of new hybrids by comparative analysis of these traits. We examined the invasive potential of a recently confirmed natural hybrid between the invasive Sphagneticola trilobata, one of the 100 worst invasive species worldwide, and its indigenous congener S. calendulacea. We compared growth and physiological responses of the hybrid and its parental species to different light conditions (open, natural light; shade, 25% of natural light) by conducting a common garden experiment. We then used discriminant analysis to identify those growth and physiological traits that are most different between the invasive and the non-invasive species. We found that S. trilobata had a higher growth rate, photosynthetic capacity and resource use efficiency than S. calendulacea in both the open and the shade environments, and the hybrid was more similar to S. trilobata than to S. calendulacea in these traits. Discriminant analysis suggested that the hybrid is more similar to S. trilobata than to S. calendulacea for a number of traits associated with performance, and that the hybrids had less invasive potential in the shade than in the open environment. These results indicate that the hybrid has a high invasive potential and could be an efficient invader in both open and shade environments. [ABSTRACT FROM AUTHOR]

The local spatial genetic structures of cave-associated plants are seldom studied. Given that these plants are mainly confined to small areas in and around the entrances of caves, we hypothesized that they might lack genetic structures at local scales. To test this hypothesis, we sampled two large populations (named D and T) of a critically endangered perennial herb, P rimulina tabacum, which is endemic to karst caves in southern China. We analysed nine microsatellite loci and sequenced four chloroplast DNA ( cpDNA) intergenic spacer regions to study the genetic diversity and structure within and between both populations. Both populations have distinct genetic characteristics. Samples from two subpopulations in population D showed considerable genetic divergence. This is not consistent with the hypothesis that P. tabacum has a weak genetic structure at a local scale. However, 94% of the individuals in population T shared the same multilocus genotype, which indicates little genetic structure within this population. The contributions of seed flow, pollen flow and (sub)population history to the genetic diversity and structure in each and both populations are discussed. Our study is the first to investigate local genetic diversity and structure in a cave-associated plant, and provides valuable information for the sustainable conservation of such species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109, 747-756. [ABSTRACT FROM AUTHOR]

The efficacy of a biological control agent depends upon the impact it has on the target species. We investigate the use of the obligate parasitic plant, Cuscuta campestris Yuncker as a biological control for the invasive weed Mikania micrantha H.B.K. In this experiment we test whether the impacts of the parasite on host growth, biomass allocation, photosynthesis, chlorophyll content, and soluble protein are affected by the density of the parasite. We examined the response of M. micrantha to infection densities of 0, 1, 2, 4 and 8 C. campestris seedlings per host plant. By day 30 after parasitization, C. campestris infection had significantly reduced M. micrantha biomass and the net photosynthetic rate of the 8th fully expanded leaf. These negative effects were greater as the number of parasites increased from 1 to 4 per host, but not from 4 to 8. Mikania micrantha stomatal conductance and transpiration rate were significantly reduced by C. campestris infection, but among 2, 4, 8 parasites per host there were no significant effects of infection densities on the host plants. Water use efficiency remained stable. The aerial parts of the infected M. micrantha plants at densities of 1, 2, 4 and 8 parasites per host died 83, 62, 50 and 46 d after parasitization on average, respectively. All infection densities decreased host chlorophyll content (a and b), and the infection by more than 1 parasite also significantly lowered soluble protein concentration. The results indicated that the effects of C. campestris infection on M. micrantha are density dependent, which provides a basis for refining the use of the parasite for biological control of M. micrantha. The optimal cost-effective number of parasites to control M. micrantha is 4 per host plant in the field. [ABSTRACT FROM AUTHOR]