Optimization of recurrent selection on the phenotypic value of doubled haploid lines

Summary Three methods of recurrent selection using doubled haploids (DH) are compared with the same resources: individual line selection (with one DH line per plant), selection between and within families, and selection index of family and line within family values. It seems that for low heritabilities at the individual level, the selection index method is the most efficient method, followed by the selection between and within families. Because of the difficulty in optimizing selection intensities, the selection between and within families can be less efficient than individual line selection. For very low heritabilities, it will be better to use selection index with a relatively low number of lines per haploidized plant, to minimize the rate of decrease of the effective population size. For a large range of situations, recurrent selection with only one DH line per plant seems one of the more efficient and the simpler methods.     

A model of the species rank-abundance relation for a community in an open habitat

A mathematical model is proposed to describe the relationship between the abundance and the rank of species in order from the most abundant to the least in a community in an open habitat. This model is derived as a corollary of a species-area equation (Kobayashi , 1975) which could be expected in the case where the individuals of each species are uniformly distributed over a habitat area. Numerical simulation reveals that a rank-abundance curve for a universe results in different species-area or species-individual curves according to the spatial distribution of individuals, and that the relative abundance of each species in a sample varies with sample size unless the spatial distribution of individuals is uniform. A species-individual curve obtained bySanders 's (1968) rarefaction method agrees with that observed actually only for the spatially uniform distribution. Change in the pattern of rank-abundance curve with species diversity and with sample size is discussed in relation to the present model.     

A History of and Recent Developments Concerning the Korean Peninsula Northern Limit Line (NLL)

Abstract

Measures to ease tensions and prevent military conflicts adjacent to the Korean Peninsula Northern Limit Line (NLL) are an integral part of the ongoing reconciliatory efforts between the South and the North. Despite controversies over the validity of the NLL, it has served as a de facto maritime demarcation line in the absence of an agreed-upon maritime demarcation line under the Armistice Agreement. North Korea has persistently attempted to invalidate the NLL, while South Korea has supported the status quo of the NLL as a military demarcation line. The South and North have recently created a buffer zone across the NLL in the West Sea amid talks for North Korea’s denuclearization.     

小麦高代新品系鉴定的聚类分析

采用系统聚类分析方法对小麦育种高代出圃品系进行了鉴定,依据小区产量、抽穗期、株高、穗长、公顷穗数、穗粒数、单穗重、千粒重、籽粒饱满度和角质率10个性状,将38个参试品系以离差平方和法在D2=2.083聚类水平下划分为5个类群,通过聚类分析了解各类群、类内品系之间以及与对照种的关系.初步评选出9个综合性状优良的新品系,描述了各个类群中品系的特性,为小麦高代品系鉴定提供了较为精确的定量鉴定方法.     

Coupling between line tension and domain contact angle in heterogeneous membranes

The compositional differences between domains in phase-separated membranes are associated with differences in bilayer thickness and moduli. The resulting packing deformation at the phase boundary gives rise to a line tension, the one dimensional equivalent of surface tension. In this paper we calculate the line tension between a large membrane domain and a continuous phase as a function of the thickness mismatch and the contact angle between the phases. We find that the packing-induced line tension is sensitive to the contact angle, reaching a minimum at a specific value. The difference in the line tension between a flat domain (that is within the plane of the continuous phase) and a domain at the optimal contact angle may be of order 40%. This could explain why previous calculations of the thickness mismatch based line tension tend to yield values that are higher than those measured experimentally.     

Comment on Cowling's "Spatial methods for line transect surveys"

We consider the problem of estimating the parameters of a two-dimensional Neyman-Scott process, from data collected through a line transect survey. Cowling (1998, Biometrics 54, 828-839) suggested an estimation method based on a one-dimensional K-function along the transect line. However, her expression for the theoretical K-function is wrong. In this article, we correct her K-function.     

影响农抗R──4产生菌效价营养成分的多元线性回归分析

应用多元线性回归方法分析了农抗R—4产生菌的发酵培养基成分;黄豆饼粉X_1,葡萄糖X_2,淀粉X_3,蛋白胨X_4,硫酸铵X5,CaCO_3,X_6,K_2PO_4X_7.得到了代表产素能力强弱的抑菌圈直径Y（mm）与营养成分X（g）的线性回归方程y=11．062＋0.969X_1,且此方程达到极显著水平．影响其产素能力的主要元素是黄豆饼粉.     

Comparing Power Behaviours for Some Goodness-of-Fit Test Statistics in Sparse Multinomials

This paper is concerned with the power behaviour of four goodness-of-fit test statistics in sparse multinomials with k cells. Most previous work has been concerned only with both Pearson's X² and the likelihood ratio test statistics. We consider in this study, two additional test statistics, namely, the Cressie-Read test statistic – I(2/3) and the modified Freeman-Tukey test (FT) statistic. Because k ≥ 10 in this study, a Monte Carlo procedure based on 1000 simulated samples is used to estimate the powers for the four test statistics. Alternatives on various line segments are employed. Results suggest that none of the test statistics completely dominate the other and that the choice of which test to use depends on the nature of the alternative hypothesis. These results are consistent with those obtained by West and Kempthorne (1972), although, the Pearson's χ² test statistic may be preferred because of its closer approximation to the χ² distribution in terms of the attained α levels.     

Hazard models for line transect surveys with independent observers

The likelihood function for data from independent observer line transect surveys is derived, and a hazard model is proposed for the situation where animals are available for detection only at discrete time points. Under the assumption that the time points of availability follow a Poisson point process, we obtain an analytical expression for the detection function. We discuss different criteria for choosing the hazard function and consider in particular two different parametric families of hazard functions. Discrete and continuous hazard models are compared and the robustness of the discrete model is investigated. Finally, the methodology is applied to data from a survey for minke whales in the northeastern Atlantic.     

中国春小麦株高、育性近等基因系的建立及应用

以矮败小麦和中国春小麦为材料,经过杂交和连续回交,得到了中国春小麦遗传背景的分别表现矮秆不育、矮秆可育、高秆不育、高秆可育的近等基因系。根据近等基因系各成员系的株高表现,计算出矮秆基因Rht10的降秆强度是69.8%。借助于赤霉酸处理,在幼芽期就可分出矮败中国春小麦后代的不育株与可育株。 Abstract：　Use Dwarfing Male-sterile Wheat and cv. Chinese Spring as parents, after cross and continuously back cross, the isogenic lines with Chinese Spring background were developed. These lines include dwarfing male-sterile line, dwarfing fertile line, tall male-sterile line and tall fertile line. The dwarfing intensity of gene Rht10 was calculated to be 69.8% according the differences between the isogenic lines. Treated with GA3solution, the male-sterile and fertile plants in Chinese Spring Dwarfing Male-sterile Wheat can be identified clearly when they are seedlings.     

Incorporating covariates into standard line transect analyses

An implicit assumption of standard line transect methodology is that detection probabilities depend solely on the perpendicular distance of detected objects to the transect line. Heterogeneity in detection probabilities is commonly minimized using stratification, but this may be precluded by small sample sizes. We develop a general methodology which allows the effects of multiple covariates to be directly incorporated into the estimation procedure using a conditional likelihood approach. Small sample size properties of estimators are examined via simulations. As an example the method is applied to eastern tropical Pacific dolphin sightings data.     

姜黄素对胃癌细胞系HGC-27增殖及侵袭力的影响

目的:探讨姜黄素(curcumin,Cur)对胃癌细胞系HGC-27细胞增殖及侵袭力的影响以阐明Cur的抗瘤机制。方法:采用MTT法检测不同剂量(0、10、20、30、40?mol/L)及不同处理时间(24、48、72h)的姜黄素对HGC-27细胞增殖活性的影响;Transwell侵袭实验检测姜黄素对HGC-27细胞侵袭力的抑制作用。结果:1.MTT法显示姜黄素显著抑制HGC-27细胞增殖,20μmol/L,30μmol/L,40μmol/L姜黄素处理72小时其生长抑制率分别为24.63%,32.42%,76.43%,有明显的剂量及时间依赖性,不同剂量组之间及不同处理时间组之间比较有差异显著性(P<0.05)。2.Transwell侵袭实验显示姜黄素显著抑制HGC-27细胞的侵袭力,呈剂量和时间依赖性,各剂量组与对照组比较差异有显著性(P<0.05)。结论:姜黄素通过抑制HGC-27细胞增殖和侵袭行为起到抗肿瘤作用。     

Shape variation in the mandibular symphysis of apes: An application of a median axis method

Symphyseal contours in a sample of living and fossil apes were assessed by application of the line skeleton, a form of median axis transformation. While the line skeleton offers novel opportunities for the analysis of shape, this study reaffirms previous observations that the shape of the symphysis is highly variable within great ape species, such that symphyseal morphology is not useful as a taxonomic marker. There is also little indication that symphyseal shape differs significantly between the sexes. The perception of what constitutes a salient superior or inferior transverse torus among living apes appears to be dependent on the expression of the genioglossal fossa. © 1993 Wiley-Liss, Inc.     

Cholesterol and the activity of bacterial toxins

Cholesterol may affect the activity of microbial toxins in a direct, specific way, or it may exert indirect effects because of its role in membrane fluidity, membrane line tension, and in the stabilization of rafts in the cytoplasmic membrane. The thiol-activated toxins of gram-positive bacteria, and the cytolysin of Vibrio cholerae are presented as examples of specific toxin-cholesterol interaction. Several mechanisms of indirect effects of cholesterol are discussed using examples such as Staphylococcus aureus alpha-hemolysin, aerolysin, and diphtheria toxin.     

羟基脲对人红白血病细胞株中珠蛋白基因表达和细胞分化的影响

人红白血病细胞株(HEL细胞)中珠蛋白基因表达具有自己的特点。即只表达胚胎型的γ-珠蛋白基因而不表达成人型的β-珠蛋白基因。羟基脲(Hydroxyurea)是一种抑制DNA合成的小分子有机化合物。它在临床上被用来治疗地中海贫血和镰刀型贫血。我们的实验结果表明:随羟基脲浓度增加HEL细胞的增殖速度减慢。用常规RT-PCR方法和定量PCR分析证明;用羟基脲诱导HEL细胞后,β-珠蛋白基因表达增加,α-珠蛋白基因表达减少,而γ-珠蛋白基因表达变化不明显。对参与珠蛋白表达的转录因子GATA-1和NF-E2的定量PCR分析发现:这两种转录因子的表达均增加3倍以上。因此,羟基脲可能通过某些信号传递途径促进β-珠蛋白基因表达,从而使HEL细胞趋向终末分化。     

中国生态环境过渡的一个重要地带

本文揭示沿腾冲－黑河联线的地带不仅如胡焕庸早年提出是一条人口地理界线,而且是一条生态环境界线,更重要的是,腾冲－黑河线表征的方向,在历史时期表现为全球变化的特征方向。     

Ranked Set Sampling and the Line Intercept Method: A More Efficient Procedure

Ranked set sampling is a method which may be used to increase the efficiency of the estimator of the mean of a population. Ranked set sampling with size biased probability of selection (i.e., the items are selected with probability proportion to its size) is combined with the line intercept method to increase the efficency of estimating cover, density and total amount of some variable of interest (e.g. biomass). A two-stage sampling plan is suggested with line intercept sampling in the first stage. Simple random sampling and ranked set sampling are compared in the second stage to show that the unbiased estimators of density, cover and total amount of some variable of interest based on ranked set sampling have smaller variances than the usual unbiased estimator based on simple random sampling. Efficiency is increased by reducing the number of items which are measured on a transect or by increasing the number of independent transects utilized in a study area. An application procedure is given for estimation of coverage, density and number of stems of mountain mahogany (Cercocarpus montanus) in a study area east of Laramie, Wyoming.     

Genetic divergence between isolated populations of the North Island New Zealand Rifleman (Acanthisitta chloris granti) implicates ancient biogeographic impacts rather than recent habitat fragmentation

This research investigates the extent and causal mechanisms of genetic population divergence in a poorly flighted passerine, the North Island Rifleman or Titipounamu (Acanthisitta chloris granti). While this species has a historically widespread distribution, anthropogenic forest clearance has resulted in a highly fragmented current distribution. We conducted analyses of mitochondrial DNA (COI and Control Region) and 12 nuclear DNA microsatellites to test for population divergence and estimate times of divergence. diyabc and biogeobears were then used to assess likely past dispersal scenarios based on both mtDNA and nDNA. The results reveal several significantly divergent lineages across the North Island of New Zealand and indicate that some populations have been isolated for extensive periods of time (0.7–4.9 mya). Modeling indicated a dynamic history of population connectivity, with a drastic restriction in gene flow between three geographic regions, followed by a more recent re‐establishment of connectivity. Our analyses indicate the dynamic influence of key geological and climatological events on the distribution of genetic diversity in this species, including support for the genetic impact of old biogeographic boundaries such as the Taupo Line and Cockayne''s Line, rather than recent anthropogenic habitat fragmentation. These findings present a rare example of an avian species with a genetic history more like that of flightless taxa and so provide new general insights into vicariant processes affecting populations of passerines with limited dispersal.     

Monitoring of butterflies in semi-natural grasslands: diurnal variation and weather effects

The butterfly fauna was monitored in six semi-natural grasslands in southeastern Sweden. The aim was to evaluate monitoring criteria for wind, sunshine, temperature and time of day for butterfly species richness and abundances when using the line transect method. A total of 30,111 butterflies belonging to 46 species were recorded. Data from this study suggests somewhat stricter criteria for temperature and sunshine than stated in the widely used “Pollards walk”. A sharp decline in butterfly numbers were detected at temperatures below 19°C if the proportion of sunshine of the transect walk was below 80–85%. No effect of wind speed, up to five on the Beaufort scale, on observed numbers of species or individuals were found. Several butterfly species showed well-defined diurnal rythms of flight activity, and the results indicated that transect walks can be performed between −4.5 and +4 h from the time when the sun reached its highest point. The results of this study can be used to adjust general criteria in national monitoring and also for detailed regional and local monitoring where it may be important to adjust for diurnal rhythm and weather related bias.