窖水中微生物降解污染物的关键细菌

为探究以氮、磷及有机物污染为主要特征的、窖水中参与污染物降解的关键细菌及它们之间潜在的相关关系,基于16S rRNA的微生物组学截面数据,分析了窖水中细菌群落结构与功能及其与水质因子间的相关性,并通过微生物物种的同现或相关种间作用推断模型,构建了7个微生物菌属间的共现性关联网络.结果表明,窖水中存在具有相对特定生态功能的细菌,进行着诸多活跃的与新陈代谢功能基因相关的代谢活动;窖水微生物类群共现性关联网络中大部分节点的菌属营互利共生类型的生态关系;Lacibacter、Arthrobacter、Candidatus Protochlamydia、Methylocaldum、Sulfuritalea、Mycobacterium、Aquirestis、Rhodobacter、Methylotenera等菌属拥有较高的点度中心度;较强的互作关系发生在Sulfuritalea-Rhodobacter、Azospirillum-Rhodobacter、Methylocaldum-Rhodobacter、Arthrobacter-Rhodobacter、Rhodoplanes-Rhodobacter、Candidatus Protochlamydia-Rhodobacter、Methylotenera-Rhodobacter、Rhodobacter-Aquirestis、Mycobacterium-Rhodobacter、PlanctomycesCandidatus Solibacter、Planctomyces-Legionella、Hymenobacter-Adhaeribacter、Luteolibacter-Crenothrix之间.综合分析节点微生物相关性、点度中心度及菌属间的互作强度,认为Rhodobacter、Methylocaldum、Methylotenera、Acinetobacter、Novosphingobium、Planctomyces、Hymenobacter、Luteolibacter为参与窖水污染物微生物降解的关键细菌,Rhodobacter为关键细菌的代表属.研究结果加深了对窖水中污染物微生物降解机制的认识.     

战场电磁环境复杂度与战术通信性能的相关性研究

目的为提升战场电磁环境环境复杂度评估的客观性,基于电磁环境与通信性能的相关性提出一种电磁环境复杂度评估方法。方法该方法以层次分析法和混合加权理论为基础,以典型通信系统为例,建立语音通信和数据通信设备性能和电磁环境复杂度等级的映射,并据此建立通信网系性能和电磁环境复杂度的等级映射,从目标层、准则层、指标层给出五级量化指标体系。结果在50 km×50 km典型地域中,上述评估方法给出了10部高频和10部超高频通信设备组成的通信网络各单链路通信质量,分别为Ⅳ、Ⅳ、Ⅰ、Ⅳ、Ⅲ、Ⅱ、Ⅳ、Ⅴ、Ⅳ、Ⅲ、Ⅱ、Ⅱ、Ⅲ、Ⅴ、Ⅱ、Ⅰ、Ⅴ、Ⅳ、Ⅴ、Ⅴ,并在此基础上评估了整个网系的通信质量等级和整个通信网系面临的电磁环境复杂度(Ⅳ)。结论上述研究验证了方法的可行性,同时证实了同一环境下不同设备所受的电磁环境影响具有个体差异性,整体通信网系的受影响程度有别于单一设备。研究结果可为通信网系的电磁环境适应性试验、电磁干扰效应评估等研究提供基础和有益的参考。     

Chaotic dynamics in a multispecies community

Environmental and Ecological Statistics - It is shown that community dynamics is neither haphazard nor completely directed. This is quite clear from our examination of a concrete example where...     

PREDICTING CHANGE IN NON-LINEAR SYSTEMS

Complex systems are characterizedby surprising switches to new behaviours. Evaluating and predicting these changes demands anunderstanding of the behaviour of the whole system. The combined ecosystem-climate system shows chaoticor pseudorandom behaviour, stochastic or trulyrandom behaviour, as well as simple bifurcation andsemi-stability. Semistability involves the suddenchange from a destabilized attractor to a newstable attractor which may occur after an apparentlyunpredictable time delay. We present some recentresults for analyzing time series data and for usingsimulations of non-linear models to predict these changes.     

基于统计复杂度的分数阶欠阻尼双稳系统的随机共振研究

目的研究Gaussian白噪声作用下分数阶欠阻尼双稳系统的随机共振现象。方法采用统计复杂度方法探究分数阶导数、余弦信号的幅值及频率、阻尼系数等参数对分数阶系统随机共振效应的影响。结果当这些参数变化时,分数阶系统的统计复杂度曲线和标准Shannon熵曲线会产生不同的变化趋势,且在分数阶导数q=0.3时,系统最易发生随机共振现象。此外,当信号振幅增加至0.2时,可以增强随机共振效应;相反,信号频率增大至0.07时,可以削弱此现象。结论这些因素可以有效地调节分数阶双稳系统的随机共振现象。     

On the origins of informal hierarchy: The interactive role of formal leadership and task complexity

Informal hierarchies are a common and important feature of many groups, yet we know little about the antecedent conditions that determine the strength of such hierarchies. Building on theory that has depicted hierarchy as a mechanism for reducing uncertainty and creating structure, we posit that informal hierarchies emerge most strongly in situations that are ambiguous, ill‐defined, and unstructured. Three independent studies confirm this notion, demonstrating that groups develop particularly strong informal hierarchies in situations characterized by both a lack of strong formal leadership and high task complexity. These findings support the theoretical notion that formal and informal hierarchies are closely related, but only under conditions of high task complexity in which the structuring functions of hierarchies are most crucial.     

Developmental stress impairs song complexity but not learning accuracy in non-domesticated zebra finches (<Emphasis Type="Italic">Taeniopygia guttata</Emphasis>)

Food restrictions early in life can have adverse effects on the development of adult avian song structure. Nutritional deficiencies during brain development are thought to impair the growth of neural circuits responsible for learning and production of song in adulthood. Thus, the quality of song may reflect the quality of the singer due to the costs associated with neural development early in life. Recent investigations have focused on domesticated laboratory strains of zebra finches where early dietary deficiencies have significantly reduced the complexity of song and its sexual attractiveness. Domesticated zebra finches may be more sensitive to the early effects of moderate under-nutrition on song complexity than their non-domesticated counterparts. In an aviary experiment with non-domesticated zebra finch stock, we found that song complexity when measured by a linear combination of six variables was reduced in food-restricted birds, with syllable rate and maximum syllable frequency as the principal variables affected. The restriction had no effect on learning accuracy when song phrases of experimental birds were compared to those of their fathers.This result demonstrates that early nutrition may differentially affect the development of neural processes that influence learning accuracy and song complexity. While the finding of negative effects of dietary restriction on song complexity is robust for zebra finches and is not an artefact of domestication, it does not explain why some nutritionally stressed populations of wild zebra finches have more complex songs than those from other regions of Australia characterised by greater food availability.     

Visualisation of the complexity of EUSES

The interdependencies of parameters applied in the models of EUSES are visualised in a directed connectivity graph. The parameters (inputs, defaults, state variables, outputs) are represented by boxes (nodes) and their relations by lines (edges). The visualisation, on the one hand, clarifies the complexity of the models in EUSES and, on the other hand, creates an overview and transparency. The parameters’ relations to each other can be recognised faster, and the models can be better understood. The complexity was quantified by the number (variety), kind (substance parameter, physico-chemical parameter, concentration, other parameters), and depth (dimension) of the parameter and the number of relations (connectivity). The variety of EUSES (without the modelsSimple Treat andSimple Box whose interior structure is not documented and without the effect and risk characterisation) amounts to 466, the connectivity to 961, and the maximal dimension is 21.     

Functional traits of poplar leaves and fine roots responses to ozone pollution under soil nitrogen addition

Concurrent ground-level ozone（O₃） pollution and anthropogenic nitrogen（N） deposition can markedly influence dynamics and productivity in forests.Most studies evaluating the functional traits responses of rapid-turnover organs to O₃ have specifically examined leaves,despite fine roots are another major source of soil carbon and nutrient input in forest ecosystems.How elevated O₃ levels impact fine root biomass and biochemistry remains to be resolved.This study was...     

视觉分心程度对跟车运动状态的影响

为明确驾驶人在不同复杂度的交通环境下视觉分心程度对跟车运动状态的影响,在驾驶模拟器上搭建城市、乡村和高速道路3种交通环境,利用视线遮挡方法,设置O、1和2s等3种固定时长,量化被试视觉分心程度;对26位被试进行模拟器驾驶试验,采集车辆速度、纵向加速度和车辆位置等参数;采用重复测量一般线性模型,分析视觉分心程度对上述参数...