一类SIS模型病原体毒力进化动力学分析

本文利用适应性动力学等理论对病原体的毒力演化进行分析,讨论可能出现的进化效果,能够为疾病的治疗方案设计、防控策略的制订提供一定的理论依据。通过引入经典的传染病SIS模型,应用进化入侵分析方法来讨论病原体能否产生进化分支,结合进化动力学理论研究了进化稳定性与感染者的恢复率、出生率之间的关系. 研究结果表明,如果权衡函数在进化奇异策略处是凹的,则该策略是收敛稳定并且是进化稳定的,即该策略为连续稳定策略,病原体不会产生进化分支。

新质生产力驱动全社会物流成本降低的机制与路径

新质生产力作为新时代的新动能,能够有效降低全社会物流成本。剖析新质生产力内涵和特征,探究新质生产力驱动全社会物流成本降低的机制与路径,具有重要意义。新质生产力强调技术创新、绿色可持续和智能化,符合高质量发展和数字经济时代生产力发展的要求,可解构为企业层面的数字化重构力、产业层面的协同进化力、社会层面的创新策源力。在新质生产力驱动全社会物流成本降低的过程中,数字化重构力是核心、协同进化力是基础、创新策源力是动能。其中,数字化重构力通过智能升级企业层面的物流活动,重塑企业生产运营模式,赋予企业新型生产要素、生产力和生产关系,引领企业物流从业务价值创造向多维度价值创造转变,有效降低企业层面的物流成本。协同进化力通过优化产业层面的物流链路,形成产业间技术渗透融合新特征、产业内分工协作新格局、平台化产业新生态,加快产业数智化进程、推动产业融合发展、助力产业绿色转型,有效降低产业层面的物流成本。创新策源力通过社会层面的物流结构优化、物流体系升级,打造高质量物流生态系统、创新物流商业模式、优化物流资源配置,推动社会物流全面降本。为有效降低全社会物流成本,应大力发展数字化重构力,鼓励企业加快数字物流建设。大力发展协同进化力,以物流业为核心推动现代产业协同发展。大力发展创新策源力,加快培育社会物流新优势。

李斯特菌毒力因子及其进化

李斯特菌属包含6个种,毒力各有差异。在细菌耐受外界环境、黏附侵袭及细胞内感染过程中,毒力因子各司其职又相互协作。毒力基因常聚集为毒力岛,其中PrfA依赖型毒力基因簇(LIPI-1)与内化素岛(LIPI-2)是致病种最重要的两个毒力岛。李斯特菌各个种可能来源于同一个携带有完整毒力岛的祖先,在长期进化过程中,通过基因水平转移或重组、整合等事件,演化为目前流行的6个种。噬菌体、转座子、质粒等可能扮演着毒力进化执行者的角色。一些天然非典型菌株是目前研究的热点,如含有LIPI-1的无害李斯特菌和缺失LIPI-1的塞氏李斯特菌,其演化进程可能尚未达到或已超越目前流行的状态,为李斯特菌毒力进化的研究提供了重要线索。

论护士长护理领导力的表现

护理领导力的表现,是指护士长在护理领导活动中所表示出来的护理领导力。护士长的护理领导力,主要表现在护理有机体凝聚力、护理职业任务担负力、护理事业发展使命履行力、护理共同体进化塑造力等。

区域经济韧性内涵辨析与指标体系构建

近年来,区域经济韧性成为区域经济研究的新范式,但学界对区域经济韧性的概念尚未形成共识,区域经济韧性的实践研究亟需建立一套综合评价指标体系。因此,本文通过梳理区域经济韧性概念与理论演变,提出区域经济韧性的三阶段,即工程韧性、生态韧性和演进韧性,分别分析了三阶段的内涵框架以及对三种区域经济韧性进行比较,并尝试性从抵抗力、恢复力、进化力三个维度分发展鲁棒性、风险脆弱性、内在稳定性、高流动性、结构平整性、创新性与可转型性七个层面构建相应的综合指标体系。

Damage and fracture behavior and spatio-temporal evolution of acoustic emission of sandstone before and after laser radiation

Laser technology holds significant promise for enhancing rock-breaking efficiency.Experimental investigations were carried out on sandstone subjected to laser radiation,aiming to elucidate its response mechanism to such radiation.The uniaxial compressive strength of sandstone notably decreases by 22.1%–54.7%following exposure to a 750 W laser for 30 s,indicating a substantial weakening effect.Furthermore,the elastic modulus and Poisson ratio of sandstone exhibit an average decrease of 33.7%and 25.9%,respectively.Simultaneously,laser radiation reduces the brittleness of sandstone,increases the dissipated energy proportion,and shifts the failure mode from tensile to tension-shear composite failure.Following laser radiation,both the number and energy of acoustic emission events in the sandstone register a substantial increase,with a more dispersed distribution of these events.In summary,laser radiation induces notable damage to the mechanical properties of sandstone,leading to a substantial decrease in elastic energy storage capacity.Laser rock breaking technology is expected to be applied in hard rock breaking engineering to significantly reduce the difficulty of rock breaking and improve rock breaking efficiency.

Genomic Sequencing and Molecular Characteristics of A Very Virulent Strain of Infectious Bursal Disease Virus Isolated in China

[Objective] The paper was to determine the genomic sequence of a very virulent strain of infectious bursal disease virus（IBDV）,and study its molecular characteristics.[Method] A very virulent strain（vvIBDV）（HLJ-0504） of infectious bursal disease virus（IBDV） with special characters was isolated in China and its genome was sequenced.[Result] Sequence analysis showed that segment A of HLJ-0504 was derived from vvIBDV,while segment B was from a distinct ancestor.The morbidity and mortality of HLJ-0504 was 100% and 86.7%to SPF chickens,respectively.[Conclusion] vvIBDV with distinct segment B were still circulating and the evolution of IBDV was diversified in China.Besides,it is hard to imagine that the virulence of IBDV is determined solely by segment A or B.

原生动物-病原菌互作与土壤健康综述

土壤健康是维持植物、动物和人类生命系统及陆地生态系统健康的重要保证。原生动物在土壤中分布广泛,可调控土壤微生物组、养分循环、污染物去除等众多生态过程,在维持土壤生态系统功能及土壤健康中发挥着重要作用。土壤原生动物捕食及杀菌机制与哺乳动物巨噬细胞免疫机制类似,其与细菌的相互作用,尤其是与病原菌的胞内共生关系,是影响病原菌毒力、扩散传播及感染风险的重要环境选择压力。本文总结了原生动物对病原菌毒力、进化、传播扩散的影响,以及病原菌在原生动物胞内的存活和进化机制,为预防环境病原菌富集、扩散和传播提供新的研究思路,对维持土壤健康有重要意义。

Sources and significance of variation in basal,summit and maximal metabolic rates in birds

The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates （e.g., lower and upper limits of metabolic power output） present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate （BMR; minimum normothermic metabolic rate）, summit metabolic rate （Msum; maximal thermoregulatory metabolic rate）, and maximal metabolic rate （MMR; maximal exercise metabolic rate）], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate （or daily energy expenditure） in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of： （1） the functional and mechanistic links between lower and upper limits of metabolic power output; （2） the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; （3） the shapes of metabolic reaction norms and their association with environmental variability; and （4） the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output [Current Zoology 56 （6）： 741-758, 2010].

Enhanced CO oxidation over potassium-promoted Pt/Al_2O_3 catalysts:Kinetic and infrared spectroscopic study

A series of K-promoted Pt/Al2O3 catalysts were tested for CO oxidation. It was found that the addition of K significantly enhanced the activity. A detailed kinetic study showed that the activation energies of the K-containing catalysts were lower than those of the K-free ones, particularly for catalysts with high Pt contents （51.6 k）/mol for 0.42K-2.0Pt/Al2O3 and 6：3.6 kJ/mol for 2.0Pt/Al2O3 ）. The CO reaction orders were higher for the K-containing catalysts （about -0.2） than for the K-free ones （about -0.5）, with the former having much lower equilibrium constants for CO adsorption than the latter. In situ Fourier-transform infrared spectroscopy showed that surface CO desorption from the 0.42K-2.0Pt/Al2O3 catalyst was easier than from 2.0Pt/Al2O3. The promoting effect of K was therefore caused by weakening of the interactions between CO and surface Pt atoms. This decreased coverage of the catalyst with CO and facilitated competitive O2 chemisorption on the Pt surface, and significantly lowered the reaction barrier between chemisorbed CO and O2 species.

Evolutionary Game Dynamics in a Fitness-Dependent Wright-Fisher Process with Noise

Evolutionary game dynamics in finite size populations can be described by a fitness-dependent Wright- Fisher process. We consider symmetric 2×2 games in a well-mixed population. In our model, two parameters to describe the level of player＇s rationality and noise intensity in environment are introduced. In contrast with the fixation probability method that used in a noiseless case, the introducing of the noise intensity parameter makes the process an ergodic Markov process and based on the limit distribution of the process, we can analysis the evolutionary stable strategy （ESS） of the games. We illustrate the effects of the two parameters on the ESS of games using the Prisoner＇s dilemma games （PDG） and the snowdrift games （SG）. We also compare the ESS of our model with that of the replicator dynamics in infinite size populations. The results are determined by simulation experiments.

Telomeres:Linking stress and survival,ecology and evolution

Telomeres are protective structures at the ends of eukaryotic chromosomes. The loss of telomeres through cell division and oxidative stress is related to cellular aging, organismal growth and disease. In this way, telomeres link molecular and cellular mechanisms with organismal processes, and may explain variation in a number of important life-history traits. Here, we discuss how telomere biology relates to the study of physiological ecology and life history evolution. We emphasize current knowledge on how telomeres may relate to growth, survival and lifespan in natural populations. We finish by examining interest- ing new connections between telomeres and the glucocorticoid stress response. Glucocorticoids are often employed as indices of physiological condition, and there is evidence that the glucocorticoid stress response is adaptive. We suggest that one way that glucocorticoids impact organismal survival is through elevated oxidative stress and telomere loss. Future work needs to establish and explore the link between the glucocorticoid stress response and telomere shortening in natural populations. If a link is found, it provides an explanatory mechanism by which environmental perturbation impacts life history trajectories [Current Zoology 56 （6）： 714-727, 2010].

Strength evolution law of cracked rock based on localized progressive damage model

In the light of the localized progressive damage model,the evolution law of cohesive and frictional strength with irreversible strains was determined.Then,the location and the extent of the excavation disturbed zone in one deep rock engineering were predicted by using the strength evolution law.The theoretical result is close to the result of in-situ test.The strength evolution law excels the elastic-perfectly plastic model and elasto-brittle plastic model in which the cohesive and frictional strength are mobilized simultaneously.The results obtained indicate that the essential failure mechanism of the cracked rock can be described by the cohesion weakening and friction strengthening evolution law.

Nonlinear Dynamical Behavior in BS Evolution Model Based on Small-World Network Added with Mechanism of Preferential Connection

In this paper, we introduce a modified small-world network added with new links with preferential connection instead of adding randomly, then we apply Bak-Sneppen （BS） evolution model on this network. Several dynamical character of the model such as the evolution graph, fo avalanche, the critical exponent D and T, and the distribution of mutation times of all the nodes, show particular behaviors different from those of the model based on the regular network and the small-world network.

Differential selection in HIV-1 gp120 between subtype B and East Asian variant B'

HIV-1 evolves strongly and undergoes geographic differentiation as it spreads in diverse host populations around the world.For instance,distinct genomic backgrounds can be observed between the pandemic subtype B,prevalent in Europe and North-America,and its offspring clade B＇ in East Asia.Here we ask whether this differentiation affects the selection pressure experienced by the virus.To answer this question we evaluate selection pressure on the HIV-1 envelope protein gp120 at the level of individual codons using a simple and fast estimation method based on the ratio ka/ks of amino acid changes to synonymous changes.To validate the approach we compare results to those from a state-of-the-art mixed-effect method.The agreement is acceptable,but the analysis also demonstrates some limitations of the simpler approach.Further,we find similar distributions of codons under stabilizing and directional selection pressure in gp120 for subtypes B and B＇ with more directional selection pressure in variable loops and more stabilizing selection in the constant regions.Focusing on codons with increased ka/ks values in B＇,we show that these codons are scattered over the whole of gp120,with remarkable clusters of higher density in regions flanking the variable loops.We identify a significant statistical association of glycosylation sites and codons with increased ka/ks values.

Kinetics analysis of non-isothermal decomposition of Ag_2O-graphite mixture

The thermal decomposition kinetics of Ag2O-graphite mixture was systematically studied using a differential scanning calorimeter（DSC） in terms of model-fitting Malek approach, integral master plot method and model-free advanced isoconversional method of Vyazovkin. The results showed that the thermal decomposition occurred in two stages. The first step was the decomposition process of Ag2 O to form porous silver particles as a complex process with the participation of at least two mechanisms, and the second step corresponded to the structural change from porous particles to silver bulk crystals as a single-step process.

Moral Hyperbole： Reflections on Moral Genealogy

My goal in this paper is to respond to the objection that naturalistic accounts of morality miss the thicker meaning with which we normally imbue ethics. I concur. This should lead us to doubt our thicker concepts, however, not doubt moral genealogy. Our thicker conceptions are hyperbolic, at best. The underlying algorithm of morality is the evolutionarily stable strategy： conditional cooperation. The content of such agreements can vary, however, and that is where moral hyperbole resides. Still, we like to distinguish good hyperbole from bad hyperbole, but the only standard for such appraisal is whether the hyperbole is consistent with the social glue of evolutionary dynamics.

Improved production of spiramycin by mutant Streptomyces ambofaciens

Strain improvement and medium optimization to increase the productivity of spiramycin were carried out. Of oil tolerant mutant strains screened, one mutant, Streptomyces ambofaciens XC 2-37, produced 9% more spiramycin than the parent strain S. ambofaciens XC 1-29. The effects of soybean oil and propyl alcohol on spiramycin production with S. ambofaciens XC 2-37 were studied. The potency of S. ambofaciens XC 2-37 was improved by 61.8% with addition of 2% soybean oil in the fermentation medium and 0.4% propyl alcohol at 24 hours after incubation. The suitable time for feeding propyl alcohol is at 24 hours after incubation in flask fermentation and at 20 hours after incubation in fermentor fermentation. The new process with S. ambofaciens XC 2-37 was scaled up for industrial scale production of spiramycin in a 60 m3 fermentor in Xinchang Pharmaceutical Factory, Zhejiang Medicine Company, Ltd., China, and the potency and productivity of fermentation were improved by 42.9%.

Analyzing Industrial Structure Evolution of Old Industrial Cities Using Evolutionary Resilience Theory：A Case Study in Shenyang of China

The recession and revitalization of old industrial cities concerns urban industrial evolution and its characteristics. Based on the theory of evolutionary resilience, we developed an analytical framework for the industrial structure evolution of old industrial cities, and applied the framework to a case study in Shenyang. The following conclusions are drawn. First, since 1978, Shenyang's industrial growth capacity has shown fluctuation between ‘contraction-expansion'. As the secondary industry has a much stronger expansionary and contractionary capacity for growth, this results in lacking stability leading to industrial structure transformation. Second, since 1999, the orientation towards a high-end manufacturing industry in Shenyang has weakened, and the evolution of the new and old growth path is characterized by low-end orientation. Third, since 2007, Shenyang's industrial innovation output capacity has dropped sharply which has been significantly affected by scientific and technological personnel and enterprise-owed science and technology institutions and to a less extent by R&D expenditure. We applied the resilience theory to study the industrial evolution of an old industrial city, explored new study perspectives on industrial evolution and verified the applicability of the resilience theory. This paper provides a scientific reference for understanding the recent deceleration in economic growth in the Northeast old industrial base, and for exploring new paths toward revitalization.

The Role of ICT in the Globalization of Firms

Accelerated globalization since the 1980s and particularly the 1990s and the development of web-based information and communication technologies （ICT） go hand in hand. Nonetheless, there has been little explicit research on the influence of ICT on the globalization of firms. Despite a rich literature of the implementation of ICT and the design of global information systems in firms, the influence of ICT on the globalization of firms has not been explicitly researched from a management perspective. This paper serves to provide an overview on existing literature in this field and to develop a basic framework for the study of the influence of ICT on the globalization of firms. Specifically, the paper reflects on the influence of ICT on the three subprocesses of globalization： internationalization, global network building, and global evolutionary dynamics.