大比例尺土壤保持服务制图分级方法研究

科学地编制生态系统服务空间分布图,有助于识别生态系统优先保护热点及空缺,能够为国土安全规划提供基础信息。但由于缺乏统一科学的生态系统服务分级方法,生态系统服务分布图的展示效果和制图效率都受到限制。不恰当的分级制图会误导决策者对生态系统服务空间分布特征的判断,增加生态保护决策的不确定性。以构建生态服务制图分级标准为目标,对我国6个典型县区的土壤保持服务数据展开1：25万比例尺制图分级案例研究。采用分级精度、面积均衡性、极差一致性、空间自相关一致性4个分级质量评价指标评价并比较了目前地图编制中常用的自然断点法、几何间隔法、累积比例法、等差法、分位数法5种分级算法的分级制图效果。结果表明,6个县区有相似的土壤保持服务分布特征：低值区覆盖面积大,高值区覆盖面积小。各县区土壤保持服务制图最优分级方法有差异：延庆区、丰满区最优分级方法为自然断点法;永靖县、天山区、安宁市最优分级方法为累积比例法;富阳区最优分级方法为几何间隔法。各分级方法中,累积比例法在6个县区综合制图效果最优或接近最优,适用性最好,能够较好的刻画各县区的土壤保持服务空间分布特征。本文提出的分级评价方法及其结果,可为生态系统土壤保持服务制图规范化和自动化提供科学依据。     

运用《生物化学》歌曲，辅助《生物化学》教学

《生物化学》以生物体为对象,研究其生命的化学本质,是生命科学领域的核心课程。长期以来,由于生物化学课程知识点多、范围广和内容抽象,在一定程度上会影响学生学习的自信心,压抑其学习过程中的兴趣,致使学习的积极性不高。最近10～20年里,国外将科学（science）、技术学（technology）、工程学（engineering）及数学（mathematics）的教育与艺术学（arts）,特别是与艺术学中的音乐结合实施教学,形成一种所谓的STEAM (STEM + Arts) 策略,对STEM教育进行辅助,取得了不错的效果。基于以上情况,结合国内生物化学教学实际,笔者尝试将生物化学歌曲应用于课堂教学过程中,辅助教学。生物化学歌曲可以将抽象难懂的生物化学知识转变成悦耳动听的歌曲,在教学过程中能激发学生的学习兴趣,活跃课堂气氛,使学生在学习过程中爱上生物化学;在生物化学歌曲的创作过程中,能促进学生的思考创新,内化重点难点,使深奥的问题形象化;在学习过程中用歌声展现生物化学的魅力,让知识成为有趣的知识,让其成为有趣的学习者。本文介绍了国内生物化学歌曲发展壮大历程,结合具体实例从利用生物化学歌曲引入教学、理解生物化学内容、密切联系生活三方面评论了生物化学歌曲在辅助生物化学教学中的应用,并从歌词的改编、旋律的选择、歌曲的传唱、教学的设计等方面需要注意的问题进行讨论。     

Isolation of Avian Trypanosomes by Selective Centrifugation and Subsequent Processing for Electron Microscopy

Paraffin sections are usually rehydrated before staining. It is possible to apply aqueous dye solutions without first removing the wax. Staining then occurs more slowly, and only if the embedding medium has not melted or become unduly soft after catting. To avoid this problem, sections are flattened on water no hotter than 45 C and dried overnight at 40 C. Minor technical modifications to the staining procedures are needed. Mercury deposits are removed by iodine, and a 3% solution of sodium thiosnlfate in 60% ethanol is used to remove the iodine from paraffin sections. At room temperature, progressive staining takes 10–20 tunes longer for sections in paraffin than for hydrated sections; at 45 C, this can be shortened to about three times the regular staining time. After staining, the slides are rinsed in water, air dried, dewaxed with xylene, and coverslipped in the usual way. Nuclear staining in the presence of wax was achieved with toluidine blue, O, alum-hematoxylin and Weigert's iron-hematoxylin. Eosin and van Gieson's picric acid-acid fuchsine were effective anionic counterstains. A one-step trichrome mixture containing 3 anionic dyes and phosphomolybdic acid was unsuitable for sections in wax because it Imparted colors that were nninformative and quite different from those obtained with hydrated sections. Advantages of staining in the presence of wax include economy of solvents, reduced risk of overstaining and strong adhesion of sections to slides.     

lncRNA与miRNA相互调控作用及其与肿瘤的关系研究

长链非编码RNA (long non-coding RNA,lncRNA)是一类转录本长度大于200 bp的非编码RNA,可作为人类基因组中一类重要的调控分子通过多种方式发挥其生物学功能.近年来的研究表明,lncRNA也可以作为一种竞争性内源性RNA (competing endogenous RNA, ceRNA) 与miRNA相互作用,参与靶基因的表达调控,并在肿瘤的发生发展中发挥重要的作用.本综述在简要介绍lncRNA功能研究现状和主要研究方法的基础上,进一步分析了lncRNA与miRNA之间的互相调控关系及其在肿瘤发生发展中的作用,以便为后续的研究提供新的思路.     

Adaptive morphological shifts to novel habitats in marine sculpin fishes

Sculpin fishes of the North American Pacific Coast provide an ideal opportunity to examine whether adaptive morphological character shifts have facilitated occupation of novel habitat types because of their well‐described phylogeny and ecology. In this group, the basal‐rooted species primarily occupy the subtidal habitat, whereas the species in the most distal clades are found in the intertidal. We tested multiple evolutionary models to determine whether changes in body size and changes in number of scales are adaptive for habitat use in sculpins. Based on a statistically robust, highly resolved molecular phylogeny of 26 species of sculpins, in combination with morphometric and habitat affinity data, our analyses show that an adaptive model based on habitat use best explains changes in body size and number of scales. The habitat model was statistically supported over models of neutral evolution, stabilizing selection across all habitats, and three clade‐based models. We suggest that loss of scales and reduction of body size in the intertidal may facilitate cutaneous breathing in air when tidepools become hypoxic during low tides. This study demonstrates how the combined use of phylogenetic, ecological and statistical approaches helps to identify traits that are likely adaptive to novel habitats.     

Adaptive Finite Element Analysis of the Anisotropic Biphasic Theory of Tissue-Equivalent Mechanics

Abstract

The nonlinear partial differential equations of the anisotropic biphasic theory of tissue-equivalent mechanics are solved with axial symmetry by an adaptive finite element system. The adaptive procedure operates within a method-of-lines framework using finite elements in space and backward difference software in time. Spatial meshes are automatically refined, coarsened, and relocated in response to error indications and material deformation. Problems with arbitrarily complex two-dimensional regions may be addressed. With meshes graded in high-error regions, the adaptive solutions have fewer degrees of freedom than solutions with comparable accuracy obtained on fixed quasi-uniform meshes. The adaptive software is used to address problems involving an isometric cell traction assay, where a cylindrical tissue equivalent is adhered at its end to fixed circular platens; a prototypical bioartificial artery; and a novel configuration that is intended as an initial step in a study to determine bioartificial arteries having optimal collagen and cell concentrations.     

Embodied Resource Flows in a Global Economy

This article presents a methodology for identifying critical links in global resource supply chains by tracking resources from their extraction in one region of the world economy through their embodiment in intermediate products in the same and other regions to eventual embodiment in final goods. We build on previous work that applied an absorbing Markov chain (AMC) to results obtained using an input‐output (IO) model of a single region to define a resource‐specific network within that economy. In the absence of model calculations, the AMC can also be applied to standard IO data for a past year. This article first generalizes the analytic framework from a single region to the important case of the global resource‐specific network. This network typically includes cycling of embodied resources between sectors not only within each economy, but also among regions, as subsequent rounds of intermediate products are traded. Next, we refine that analysis to exhibit a crucial subnetwork, the resource end‐use network, which only tracks the portion of the resource that ends up embodied in a specific final product in a given region. Finally, we develop techniques to distinguish key branches of these networks and provide detailed insights about the structure of global resource dependence. A numerical example is applied to results of scenario analysis using an IO model of the world economy. Two alternative scenarios are compared. In each scenario, embodied resources are carried over specific branches of a global network in three regions using three resources to produce four goods.     

Acidophytic shrublands in the north-west of the Italian peninsula: Ecology,chorology and syntaxonomy

Abstract

The shrublands growing on siliceous and/or calcium-poor substrata of the hilly and mountainous areas of north-western and central Italy were studied. This secondary vegetation is dominated by several acidophilous shrubs like Ulex europaeus, Cytisus scoparius, Erica arborea, E. scoparia and Calluna vulgaris. The synecology, synchorology and syntaxonomy of this vegetation was studied using multivariate methods, and discussed in comparison with similar types described in other zones of the Italian peninsula. Two new subassociations are proposed here: Erico arboreae-Arbutetum unedonis genistetosum germanicae and Calluno-Sarothamnetum ericetosum scopariae. Calluno-Sarothamnetum is typified; the Sarothamnion alliance is discussed and referred to Cytisetea scopario-striati. The presence of Calluno-Ulicetea and Cytisetea scopario-striati classes is discussed, and a syntaxonomical scheme is proposed.