中国木质林产品碳储量及其减排潜力

伐后木质林产品作为森林生态系统碳循环的一个组成部分,对森林生态系统和大气之间的碳平衡起着至关重要的作用.为准确合理估算木质林产品碳储量和我国参加气候变化谈判提供依据,在达喀尔会议上确立的3种估算方法框架下,即:储量变化法、生产法和大气流动法,利用寿命分析法和逐步递归法以及国内参数计算我国木质林产品的碳储量,且对生产法的应用提出了一种新假设思路,并分析我国木质林产品在替代建筑材料方面的减排潜力,结果显示:①分别利用储量变化法、生产法和大气流动法估算我国1961～2004年木质林产品的碳储量变化,证明我国的木质林产品是一个碳库,并且这个碳库的碳储量不断在增长;② 3种方法估算1961～2004年木质林产品碳储量的年平均增长量分别是11.73Mt · a-1(Mt=106t)、9.31Mt · a-1和7 90Mt · a-1;③木质林产品在建筑材料领域的替代作用以及延长其使用寿命使其减排潜力增大;④从碳储量计量和估算的难易程度来看,储量变化法的应用可能对我国较为有利;⑤针对生产法假设的实践应用,还需要进一步的研究.     

An Adjusted Likelihood Ratio Approach Analysing Distribution of Food Products to Assist the Investigation of Foodborne Outbreaks

In order to facilitate foodborne outbreak investigations there is a need to improve the methods for identifying the food products that should be sampled for laboratory analysis. The aim of this study was to examine the applicability of a likelihood ratio approach previously developed on simulated data, to real outbreak data. We used human case and food product distribution data from the Norwegian enterohaemorrhagic Escherichia coli outbreak in 2006. The approach was adjusted to include time, space smoothing and to handle missing or misclassified information. The performance of the adjusted likelihood ratio approach on the data originating from the HUS outbreak and control data indicates that the adjusted approach is promising and indicates that the adjusted approach could be a useful tool to assist and facilitate the investigation of food borne outbreaks in the future if good traceability are available and implemented in the distribution chain. However, the approach needs to be further validated on other outbreak data and also including other food products than meat products in order to make a more general conclusion of the applicability of the developed approach.     

生态系统多功能性的测度方法

生物多样性与生态系统多功能性(biodiversity and ecosystem multifunctionality, BEMF)之间的关系是目前生态学研究的一个热点, 其中, 生态系统多功能性(EMF)的测度方法是研究该问题的技术关键。由于缺乏统一的认识, 目前存在多个多功能性的测度方法, 这使人们对生物多样性与生态系统多功能性之间关系的理解复杂化。本文介绍了国际上常用的单功能法、功能-物种替代法、平均值法、单阈值法、多阈值法、直系同源基因法和多元模型法的原理及其特点, 并对其中较难理解的多阈值法进行了举例说明, 希望能对理解EMF的测度方法有所帮助。本文按不同的EMF测度方法对已发表的有关文章进行了归类, 以期帮助读者更好地选择EMF的测度方法。由于缺乏相对统一的、代表各个层次的生态系统功能的测度方法, 导致不同的研究结果难以相互比较, 严重限制了生物多样性与生态系统多功能性研究的发展; 所以, 研发新的、具有普遍适用性的EMF测度方法已成为当务之急。     

Methodology for estimating the abundance of rare animals: seabird nesting on north east Herald Cay

We discuss the problem of estimating the number of nests of different species of seabirds on North East Herald Cay based on the data from a 1996 survey of quadrats along transects and data from similar past surveys. We consider three approaches based on different plausible models, namely a conditional negative binomial model that allows for additional zeroes in the data, a weighting approach (based on a heteroscedastic regression model), and a transform-both-sides regression approach. We find that the conditional negative binomial approach and a linear regression approach work well but that the transform-both-sides approach should not be used. We apply the conditional negative binomial and linear regression approaches with poststratification based on data quality and availability to estimate the number of frigatebird nests on North East Herald Cay.     

Powerful Exact Unconditional Tests for Agreement between Two Raters with Binary Endpoints

Asymptotic and exact conditional approaches have often been used for testing agreement between two raters with binary outcomes. The exact conditional approach is guaranteed to respect the test size as compared to the traditionally used asymptotic approach based on the standardized Cohen''s kappa coefficient. An alternative to the conditional approach is an unconditional strategy which relaxes the restriction of fixed marginal totals as in the conditional approach. Three exact unconditional hypothesis testing procedures are considered in this article: an approach based on maximization, an approach based on the conditional p-value and maximization, and an approach based on estimation and maximization. We compared these testing procedures based on the commonly used Cohen''s kappa with regards to test size and power. We recommend the following two exact approaches for use in practice due to power advantages: the approach based on conditional p-value and maximization and the approach based on estimation and maximization.     

Investigation of an expert systems approach to bacterial identification

An investigation was carried out to assess the feasibility ofusing an expert systems approach to assist in the identificationof unknown isolates of bacteria. A system was developed usingLisp which utilized the knowledge stored in standard bacteriologicaltexts. A comparison of the expert systems approach and the probabilisticapproach based on Bayes Theorem was made together with the advantagesand disadvantages of each approach. Received on November 5, 1990; accepted on February 20, 1991     

Scattering of Surface Plasmon by Nano-probe. Influence of the Local Field Inhomogeneity

The surface plasmon polariton scattering by nanoparticle was considered in the frame of approach based on the effective susceptibility concept. The main feature of the approach is taking into account the inhomogeneity of the local field at the nanoparticle. The inhomogeneity strongly influences on the effective susceptibility of the particle formation. The approach allowed to explain the nonmonotonic behavior of scattered field intensity at the detector placed in far zone on the distance between the particle and a surface obtained experimentally in reported earlier by other authors.     

A resynthesis of the primordial and circumstantial approaches to ethnic group solidarity: Towards an explanatory model

Social scientists who have attempted to explain ethnic group solidarity have tended to use either the primordial or the circumstantial approach. The first approach accounts for strong ethnic attachments on the basis of their ineffable affective significance. Moreover, this affective significance most often surrounds images of the group's distinctive past, thus giving a historical dimension to the concept of primordialism. The second approach views ethnic group solidarity as resulting from certain social circumstances, both internal and external, under which the members of the group exist. It is argued that neither approach alone offers a sufficient explanation ‐ i.e., that the primordial approach cannot readily account for fluctuating ethnic group solidarity and that the circumstantial approach tends to ignore the affective significance of ethnic ties ‐ and that previous attempts to synthesize them have been inadequate as explanatory models. Such a synthetic model is offered, which is based on the oppositional approach originated by Edward Spicer and which maintains that fluctuating ethnicity, along with fluctuating primordial sentiments, can be best explained on the basis of the circumstance of fluctuating opposition.     

Linkage analysis of GAW14 simulated data: comparison of multimarker, multipoint, and conditional approaches

The purposes of this study were 1) to examine the performance of a new multimarker regression approach for model-free linkage analysis in comparison to a conventional multipoint approach, and 2) to determine the whether a conditioning strategy would improve the performance of the conventional multipoint method when applied to data from two interacting loci. Linkage analysis of the Kofendrerd Personality Disorder phenotype to chromosomes 1 and 3 was performed in three populations for all 100 replicates of the Genetic Analysis Workshop 14 simulated data. Three approaches were used: a conventional multipoint analysis using the Zlr statistic as calculated in the program ALLEGRO; a conditioning approach in which the per-family contribution on one chromosome was weighted according to evidence for linkage on the other chromosome; and a novel multimarker regression approach. The multipoint and multimarker approaches were generally successful in localizing known susceptibility loci on chromosomes 1 and 3, and were found to give broadly similar results. No advantage was found with the per-family conditioning approach. The effect on power and type I error of different choices of weighting scheme (to account for different numbers of affected siblings) in the multimarker approach was examined.     

Mechano-geometric generative rules of morphogenesis

The ideographical approach aimed at detecting specific causative relationships within the process of development prevails in modern embryology. The present work considers the possibilities of using the nomothetic approach aimed at putting forward nonspecific general laws based on the general scientific theory of self-organization and can be formulated in morphomechanical terms based on feedback links between passive and active mechanical stress. The perspectives of this approach and the involvement of genetic factors in the regulation of feedback links are discussed.     

A simple method for phylogenomic inference using the information of gene content of genomes

Many studies have been contributed to the inferences of phylogenies. Some studies are based on a single-gene (family), and some are based on entire genome data. In this paper, we propose a total loss genome distance approach based on gene content information to inferring phylogenies. Through various simulations, we demonstrate and evaluate the proposed approach. We compare it with some other approaches built upon gene content or extended gene content. Overall, the proposed approach performs equally well as the other methods do and is more efficient than some of the methods. We apply our approach to 34 microbial complete genomes from COG. The reconstructed tree agrees with the results from other approaches and the tree supports the concept of universal trees.     

新生隐球菌总RNA抽提方法的实验研究

目的探讨快速获取高质量的新生隐球菌总RNA的实验方法。方法选取新生隐球菌的荚膜株、荚膜缺陷株,分别设计采用4种方法提取总RNA:酸洗玻璃珠法、液氮研磨法、异硫氰酸胍一步法、冷酸洗玻璃珠联合Yeast RNA kit法。用紫外线分光光度计测量其OD260、OD280的值,并且进行琼脂糖凝胶电泳,同时应用定量PCR法鉴定RNA质量。结果酸洗玻璃珠法、液氮研磨法、异硫氰酸胍一步法、冷酸洗玻璃珠联合Yeast RNA kit法的RNA产量分别为0.2μg/105细胞、0.4μg/105细胞、0.1μg/105细胞、0.6μg/105细胞。结论冷酸洗玻璃珠联合Yeast RNA kit法提取的RNA均一性和完整性最好,是简便、快捷地提取具有荚膜和细胞壁双重屏障的新生隐球菌RNA的理想方法。     

Approach behaviour and embryonic visual experience in chicks: studies on the effect of rate of visual flicker

It has been demonstrated that visual stimulation during the latter part of embryonic development will have its effect on subsequent approach behaviour in the chick. Stimulation here had been of a non-specific type, i.e. mere presence or absence of illumination. This study was conducted to see how much specific stimulation like visual flicker applied during the latter part of embryonic development would affect approach to the same or similar stimuli. In experiment 1 extremely slow flicker (6·6 and 20 c/min) was applied to the eggs under incubation. Treatment groups were tested for approach on flickering and non-flickering stimuli after hatching. Results show that exposing the eggs to flicker has an effect on approach behaviour. Groups that received flicker at a rate of 20 c/min approach faster than those which received flicker at the rate of 6·6 c/min. A significant improvement over trials was only found in the group which received flicker of 20 c/min during the embryonic period. In experiment 2 which employed a range of very much faster flicker no significant treatment effects became apparent. These results suggest that visual flicker as embryonic stimulation is effective in priming the embryo to yield better approach performance after hatching. Results of experiment 2 indicate that the effect of flicker as embryonic stimulation may operate over a certain range in affecting subsequent approach performance.     

Herbivory and plant resource competition: a review of two interacting interactions

This review discusses the prevalence and potential for interactive effects between herbivory and competition on plant growth and biomass, and it is apparent that such effects typically arise when there is a mismatch between the spatial scale of herbivore behaviour (food or patch choice) and the spatial heterogeneity of the plant community. Historically, such interactive effects have been examined using two approaches. Studies using the first approach have excluded plant neighbors and herbivores in a factorial experiment, and scored effects on plant biomass. Studies using the second approach have observed herbivore abundance or herbivory on plants with or without plant neighbors, and have identified a large number of mechanisms underlying such interactive effects. The two types of studies have produced somewhat conflicting results, where interactive effects have been commonly observed in studies using the second approach and only rarely in studies using the first approach. This is most likely a consequence of a biased choice of study systems, where studies using the first approach have primarily studied mammalian herbivory while studies using the second approach have been more focussed on insect herbivory. Moreover, studies using the first approach have typically been very small-scale manipulations and this probably precludes most possible interactive effects in systems with mammalian herbivory. This points to the fact that studies examining interactive effects of herbivory and plant competition should more carefully consider the behaviour and life history of herbivores included in the study prior to the design of removal experiments.     

信号适体的设计策略及应用

信号适体兼具有分子识别和信号转导的功能.从随机寡核苷酸库中筛选出的适体,要经过合理设计和筛选后修饰,才具备信号转导功能.信号适体可分为标记和非标记两大类.本文着重介绍荧光标记信号适体的设计策略,包括基于荧光偏振分析标记一个荧光基团,及基于荧光共振能量转移同时标记荧光基团、淬灭基团,或两个荧光基团的信号适体(包括分子信标适体、结构转换和原位标记信号适体).非标记信号适体的设计,有嵌合法、置换法、光转换复合物法,及适体－多聚物偶联法.此外,亦可直接从体外筛选出信号适体.信号适体的诸多优点利于其用于生物传感器及均相液相中实时蛋白识别与定量分析.     

A New Trend in the Experimental Methodology for the Analysis of the Thioflavin T Binding to Amyloid Fibrils

The studies on the determination of the characteristics of the amyloid fibril interaction with the dye were based on the analysis of the dependence of the ThT fluorescence intensity on its concentration in the solution containing the amyloid fibrils. In the present work, we revealed that this intuitive approach provided erroneous data. We propose a new approach which provides a means for characterizing the interaction of thioflavin T (ThT) with amyloid fibrils and for determining the binding stoichiometry and binding constants, absorption spectrum, molar extinction coefficient, and fluorescence quantum yield of the ThT bound to the sites of different binding modes of fibrils. The key point of this approach is sample preparation by equilibrium microdialysis. The efficiency of the proposed approach is demonstrated via the examination of the ThT binding to insulin and Aβ42 fibrils as well as to the native form of the Electrophorus electricus acetylcholinesterase. We show that the peculiarities of ThT interaction with amyloid fibrils depend on the amyloidogenic protein and on the binding mode. This approach is universal and can be used for the analysis of binding mechanism of any dye that interacts with its receptor. Therefore, the proposed approach represents an important addition to the existing arsenal of means for the diagnostics and therapy of the neurodegenerative diseases.     

Plasmid transformation of Bacillus cereus on cellophane membranes

A simple approach to test the ability of bacteria to undergo natural genetic transformation is suggested. The basic feature of the approach is the cultivation of bacterial cells in the presence of exogenous (plasmid) DNA on cellophane membranes placed successively on nutrient and selective agar. Using this approach the ability of Bacillus cereus for "natural" genetic transformation was detected. Transformation frequencies varied from 10(-8) to 10(-6).     

Vlasov equation in terms of canonical variables

A new approach to the perturbation theory for the Vlasov equation is discussed. The approach is based on the expansion of the Hamiltonian in powers of the canonical variables about their equilibrium values. Unlike the traditional approach, the proposed perturbation theory provides energy conservation in every order. In particular, solutions to linearized equations are constructed that carry certain energy and momentum. The influence of decay processes on the kinetic beam-plasma instability is also discussed.     

重要物种优先保护种群的确定

由于同一物种不同种群的重要性不同、用于物种保护的资金有限以及保护与发展经济之间的矛盾,因此对于重要物种（尤其是濒危种类以及农作物和驯化动物的野生近缘种）需要确定保护什么以及保护哪儿。目前确定优先保护种群的方法主要有3类,分别为基于遗传变异、基于遗传差异性和基于遗传贡献率的方法。基于遗传变异的方法主要是根据遗传变异程度（尤其是等位基因多样性）来确定优先保护的顺序,但忽略了种群之间的遗传差异性,这容易使得存在于遗传变异程度较低的种群中的特有等位基因得不到有效保护。而基于遗传差异性的方法（如确定进化显著单元）则是从遗传分化程度的角度考虑优先性,即独特性越强的种群越具有保护价值。基于遗传贡献率的方法由于综合考虑了遗传多样性和差异性,最适合于确定哪些种群需要优先保护。我国开展此类研究十分必要。     

The cost of complexity in forecasts of population abundances is reduced but not eliminated by borrowing information across space using a hierarchical approach

Anticipating ecological changes is paramount if we are to manage biodiversity and the services they provide to humanity. When forecasting population abundances, studies have shown that simple statistical models often have better forecast performance than complex models. These studies have evaluated forecasts of models fitted separately to data from single sites (single-site approach). Here, we aim to contrast the forecast performance and forecast horizon between a single-site approach and a hierarchical multi-site approach where a single model is fitted to data from multiple-sites, and to investigate how they vary with model complexity. We used 5273 population time series on 84 species from the Swedish breeding bird survey program, and found that simple models on average had better forecast performance and forecast horizon than complex models for both the single- and the multi-site approach. However, the cost of complexity was considerably reduced under the multi-site approach, while the proportion of species for which complex models had better forecast performance than simple models was also much larger than under the single-site approach. This suggests that the multi-site approach is useful for inclusion of more detailed processes which may benefit forecasts for some species and which are of importance for managers. Still, our results are in line with some previous studies suggesting that it is surprisingly difficult to construct complex models that, on average, beat trivial baseline forecasts.