城市绿地供需的差异与联系研究进展

作为连接城市绿地与居民需求的重要概念,绿地供需是城市绿地研究和规划决策的重要内容。识别城市绿地供给与需求的区别和关联,有助于城市绿地合理配置、人类福祉提升和城市的可持续发展。本文梳理2016—2020年城市绿地供需研究的主要议题和研究模式,探讨不同议题的差异与联系,并对未来城市绿地供需关系研究提出建议。综述发现,多数研究从供给或需求一方面开展研究,较少将城市供给与需求研究结合一起分析。供给方面主要关注绿地时空分布特征与生态系统服务供给,需求方面侧重于研究居民对绿地的主观偏好与行为。绿地供给、需求的研究对象、研究尺度与研究指标存在较大差异,是二者难以建立联系的主要因素。今后的研究应注重绿地供需匹配的情况。基于主观偏好/客观指标的绿地供需整合研究,是城市绿地供需关系研究的重要方向。     

Analysis of “nontraditional” relationships under assortative mating

The set of conditions on the genetical and developmental mechanisms of quantitative characters as well as on selection and mating system presented in (Gimelfarb, 1981) is expanded, thus enabling one to obtain the genotypic covariances between relatives for a larger variety of relationships. It is also demonstrated that the frequency of a relationship in a population under assortative mating may in general be different from the frequency of this relationship in the population under random mating. A subpopulation of relatives is not necessarily a representative sample of the whole population with respect to the quantitative character distribution. However, for any relationship which is a combination of descendant-ancestor, full sib, Type 1 and Nth uncle-niece relationships, its frequency in a population under assortative mating is the same as in the population under random mating, and the subpopulation of such relatives is a representative sample of the whole population.Paper No. 6620 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina. This investigation was supported in part by NIH Research Grant No. GM 11546 from the National Institute of General Medical Sciences     

酵母三杂交系统的应用研究进展

1996年,酵母三杂交技术被研究应用于筛选RNA结合蛋白.本介绍了酵母三杂交系统的原理、应用、前景和存在的不足及局限,并分析其原因,总结了在过去8年中利用此方法所取得的成就.在酵母双杂交基础上发展起来的酵母三杂交系统,其应用范围已扩大到蛋白质-蛋白质、蛋白质-RNA、蛋白质-小分子药物间的相互作用等更加广泛的研究领域.     

Assortative mating for a quantitative character

Phenotypic assortative mating is investigated for a character determined by additive loci without dominance and a stochastically independent environment. Conditional-expectation arguments are used to calculate the equilibrium values of the phenotypic variance and the correlation between sundry relatives. For the latter, it suffices to suppose that the regressions of an individual's genotype on his phenotype and of his phenotype on that of his mate are linear. For the former, linearity of the regression of the allelic effects on the phenotype is also posited. The biological implications of these assumptions are discussed.Supported by National Science Foundation Grant DEB81-03530     

国产磨芋属的染色体核型报道(Ⅱ)

本文报道了磨芋属(Amorphophallus Blume)三个种(其中包括两个最近发现的新种)的染色体数目和核型,其核型公式分别是: 1.结节磨芋 K(2n)=2x=26=20m(2SAT)+6sm; 2.疣柄磨芋 K(2n)=2x=28=2M+16m+8sm+2st; 3.矮磨芋 K(2n)=2x=26=20m+4sm+2st; 本文还在报道磨芋(A.konjac)两个居群的核型的基础上,提出不同居群磨芋的核型存在一定异;并比较了矮磨芋和磨芋两个居群的核型,从核型上分析了它们之间可能的关系。     

芦芽山植物群落种间关系的研究

通过采用 2× 2列联表的 Fisher精确检验、Pearson相关分析和 Sperman秩相关分析等方法对芦芽山植物群落的种间关系进行了分析。结果表明 ,研究物种关联程度大小时 ,Sperman检验的灵敏性要高于 Pearson相关 ,使用 Sperman秩相关分析得出的结果较好 ,分层对种间关联性进行的研究发现 ,极显著相关和显著相关种对多发生于各层的优势种及次优势种间 ,并依层次不同而不同 ,其中草本层极显著相关种对最多 ,灌木层次之 ,乔木层最少     

Study of the interaction between rabbit cardiac contractile and regulatory proteins. An <Emphasis Type="Italic">in vitro</Emphasis> motility assay

A series of experiments was performed in an in vitro motility assay with reconstructed thin filaments to obtain pCa-force relationships for cardiac isomyosins V1 and V3. Two concentrations of each isomyosin (200 and 300 microg/ml) on the surface of a flow cell were tested. Isometric force was estimated as the amount of actin-binding protein, alpha-actinin, stopping thin filament movement. It was found that the amount of alpha-actinin stopping the movement at saturating calcium concentration for V3 was twice higher than for V1 at both concentrations of isoforms. Hill coefficients of cooperativity (h) were determined for pCa-force relationships. The value of h did not differ significantly for isoforms at 300 microg/ml of protein (h was 1.56 for V1 and 1.54 for V3). However, the Hill coefficient was higher for V3 isoform at 200 microg/ml (h = 2.00 and 1.76 for V3 and V1, respectively). Importantly, the Hill coefficient increased for both isoenzymes when their concentrations were decreased. The connection between Hill coefficient and cooperative interactions between cardiac contractile and regulatory proteins is analyzed in detail.     

A general linear model for the genotypic covariance between relatives under assortative mating

A linear model for the genotypic covariance between relatives under assortative mating comprising the classical linear model and the model of selective assortative mating is proposed. The general conditions on the genetical and developmental mechanisms of quantitative characters, as well as on selection and the mating system, on which the model is based, are explicitly stated and discussed. A classification of different relationships is presented and it is shown that these conditions are sufficient to obtain the genotypic covariance between relatives only if the relationship is a combination of descendant-ancestor, full sib, Type 1 and Nth uncle-niece relationships. All the traditional relationships, i.e., those for which the covariances of the relatives have been obtained in the literature, fall into this category. These conditions also ensure that the regression of the individual's genotypic value on the genotypic value or phenotype of any of its ancestors is always linear.Paper No. 6619 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, North Carolina. This investigation was supported in part by NIH Research Grant No. GM 11546 from the National Institute of General Medical Sciences     

Anonymous communications in the Internet

With the growth and acceptance of the Internet, there has been increased interest in maintaining anonymity in the network. By using traffic analysis, it is possible to infer who is talking to whom over the Internet. We present a novel approach to hide the senders and the receivers of messages. Routes are chosen and frames traverse these routes. Each frame consists of a token and a node can send a message through a frame only when the corresponding token is free. The advantage of our protocol is that it poses limited bandwidth overhead when there is at least some traffic, while posing minimal bandwidth overhead when there is no traffic at all.

浅论如何持续有效地推进产学研创新联盟合作

产学研创新战略联盟是提升产品市场竞争力的手段,它集合了产业链中各相关单位资源,提供了解决瓶颈技术的平台,利益分享。该文介绍了联盟创建、成员的选择、风险控制、日常管理、利益分享等方面的经验。     

中国汉族儿童少年身高发育城乡差别的变化趋势

本文分析了1985—1995年中国26个省市7—18岁城乡儿童少年身高的发育趋势。总体上看 ,城乡差别明显缩小 ,男女生 7—18岁平均缩小0.55cm和0.64cm,其中以青春发育突增期缩小幅度最大。各省市的变化趋势不一致 ,南方省市缩小较北方明显。     

珙桐群落种间关系的研究

用方差比率法(VR)和在2×2联列表基础上应用Jaccard指数、Dice指数和Pearson相关系数、Spearman秩相关系数对卧龙自然保护区三江珙桐群落种间关系进行了分析,结果表明珙桐群落中主要种群在总体上表现出正关联,群落中种间联结的显著度较低,仅有7对联结显著,珙桐与总状山矾呈显著负联结,与稠李呈极显著负联结。大多数种对间关联程度较低,存在极大排斥性的种对较少,暗示目前珙桐群落处于较成熟阶段。研究种间关系时,种间关联性测定指标结合相关系数分析得出的结果较好,最后对珙桐的保护提出了一些建议。     

Mathematical model for the alcoholic fermentation in batch culture: Comparison between complete and incomplete factorial (33) designs

Surface response methodology was used to study the effects of three variables, viz. total reducing sugars (116–222 g l^?1), yeast inoculum concentration (10–30%) and supplemented inorganic nitrogen as (NH₄)₂SO₄ (1–3 g l^?1) on the production of ethanol.The complete and incomplete factorial designs (3³) were compared through the residual analysis of variance. Since there was no statistically significant difference at the 5% level, on the basis of cost-efficiency and space limitations, it was recommended to use incomplete factorial design constituting 12 treatments with three repetitions in central point totalling 15 experiments which control the batch alcoholic fermentation.     

国内外转基因作物产业化的比较

当前,全球转基因作物研发和产业化迅猛发展, 创造了巨大的经济、社会和生态效益。转基因作物产业化发展的快慢, 是关系到我国农业可持续发展和提高农产品国际竞争力的重大问题。就国内外转基因作物的产业化进行了优劣势比较, 并从影响转基因作物产业化的技术瓶颈和安全性监管两方面进行了探讨。     

Competition between different strains of Streptococcus cremoris

Abstract Streptococcus cremoris strain HP was found to grow poorly on agar plates under aerobic conditions in comparison to several other strains of S. cremoris (Wg2, ML1, AM1, E8). This made it possible to determine the numbers of strain HP in mixed cultures with other strains under different culture conditions. None of the mixtures was stable in batch cultures as a result of differences in the maximum specific growth rate. In continuous culture under lactose limitation strain HP outcompeted strains E8 and ML1 at low dilution rates, but at high dilution rates and in batch culture the reverse was observed. This represents another example of crossing μ-s curves in anaerobic bacteria.     

内蒙古地区锦鸡儿属3种植物叶脉序比较研究

以内蒙古地区锦鸡儿属3种植物小叶锦鸡儿、中间锦鸡儿、柠条锦鸡儿为对象,利用光学显微镜观察了它们的叶脉序特征,并测定相应的数量指标.结果表明,3种锦鸡儿植物叶片在脉序类型、三级脉类型、高级脉类型、盲脉类型及分枝、网眼形态上没有明显的差别;在各级脉粗细、二级脉夹角、三级脉疏密度以及网眼发育等特征上均表现出随地理分布自东向西逐步递增、递减、密集和趋于完善的变化特点,且有交叉重叠现象;在一级脉的粗细、二级脉的分枝、二级间脉的类型、三级脉疏密等特征上,中间锦鸡儿和柠条锦鸡儿差异较小.研究发现,内蒙古地区锦鸡儿属3种植物在多数叶脉序形态特征和一些数量化指标上没有明显的差异,其亲缘关系较为紧密,但中间锦鸡儿和柠条锦鸡儿在种间关系上可能更为接近;3个种自东向西呈现很强的相似性和渐变性分布,表现出地理渐变的趋势.     

糖生物学和糖组学

糖生物学和糖组学,虽然都是研究糖类在机体中的作用,但是,它们分别有不同的视角。糖生物学是沿袭了糖化学、糖生物化学发展而来,着重研究糖类和蛋白质的相互作用;而糖组学则源于基因组学,以基因编码糖基转移酶为起始,由这些酶得到糖组,进而开展糖组的研究。     

关于数量化I方法的自变量之间交互作用计算

自变量之间存在交互作用时,在应用数量化方法Ｉ时如何计算自变量间的交互作用建立数量化方程．