Exploring variation in fitness surfaces over time or space

As the number of studies estimating selection on multiple traits has increased in recent years, fitness surfaces have become a fundamental tool for understanding multivariate selection and evolution. However, rigorous statistical comparisons of multivariate selection surfaces over time or space have been limited to parametric analyses of selection coefficients estimated using a quadratic regression model. Although parametric comparisons are useful when selection is approximately linear or quadratic in nature, they are limited when confronting the complex nature of rugged fitness surfaces. Here, I present a novel solution to comparing nonparametric fitness surfaces over time or space. Using a Tucker3 tensor decomposition, which is essentially a higher order principal components analysis, I show how major features of fitness surfaces can be compared statistically. Combined with a bootstrap algorithm, I develop three statistical tests that identify (1) differences in the shape of nonparametric fitness surfaces, (2) differences in the contribution of each surface to variation in fitness across time or space, and (3) specific areas of the surfaces (trait combinations) that vary significantly over time or space. I illustrate the tensor decomposition and statistical analyses using idealized fitness surfaces.     

Population parameters and growth of Myzus persicae Sulzer (Hemiptera: Aphididae) under elevated CO2 concentrations in the air

The effects of three different CO₂ concentrations (400, 600, and 1000 ppm) on the population parameters and growth of the green peach aphid, Myzus persicae, were examined. Raw life history data from M. persicae were analyzed using an age-stage, two-sex life table to take into account the viable development rate among individuals. The population projections of M. persicae indicate the stage structure and variability of the population growth under different CO₂ concentrations based on an age-stage, two-sex life table analysis. Significantly longer oviposition duration and higher fecundity were observed under elevated CO₂ (600 and 1000 ppm) than those under ambient CO₂ (400 ppm). Furthermore, the M. persicae population reared under elevated CO₂ concentrations showed higher intrinsic and finite rates of population increase than under ambient CO₂ concentrations. These results indicate that the population parameters and growth of M. persicae were positively influenced in the fecundity by elevated CO₂ concentrations relative to the ambient CO₂. These findings indicate that it is basically remained to understand the direct effects of CO₂ elevation on the host plants, and the interaction between the host plants and M. persicae in the same CO₂ concentration for establishing more realistic population growth model systems for M. persicae in the aerial environment rising CO₂ concentration level.     

Application dependency of lca methodology: Key variables and their mode of influencing the method

The reason to perform an LCA is essentially to use it in support of a decision. A decision gives rise to a change somewhere in society compared to a scenario in which this decision was not taken. The key requirement for the LCA in any application is therefore, that it shall reflect the environmental change caused by the decision. It is found, that the need to differentiate LCA methodology for the use in different applications is born by a few key characteristics of the decision to be supported. The first key characteristic is the environmental consequence of the decision, i.e. the nature and extent of the environmental change caused by the decision. When modelling the environmental change, its extent in time and space will differ between decision types, thus giving rise to different requirements, primarily for the scoping and inventory phases of the LCA. Furthermore, some decisions will imply trade-offs between different impact categories, while others will not, thus causing different requirements for the impact assessment. The second key characteristic is the social and economic consequence of the decision, the magnitude of which will influence the need for certainty, transparency and documentation. The third characteristic is the context in which the decision is taken, including the decision maker and interested parties, implicitly influencing the impact assessment and weighting.     

Retinohypothalamic projection in the mouse: Electron microscopic and iontophoretic investigations of hypothalamic and optic centers

The problem of the direct retinohypothalamic projection in mammals (Moore, 1973) was reinvestigated in the laboratory mouse by electron microscopy and cobalt chloride-iontophoresis. The time-course of the axonal degeneration in the suprachiasmatic nucleus was studied 3, 6 and 12 h, 1, 2, 4, 6, 9 and 12 days after unilateral retinectomy. Specificity of the degenerative changes was controlled by investigation of the superficial layers of the superior colliculus. The ratio of crossed to uncrossed optic fibers could could be determined by counting degenerating structures (axons and terminals) in the optic chiasma and the ipsilateral and contralateral areas of the optic tract, the suprachiasmatic nucleus, and the superior colliculus. The number of degenerating axons in the suprachiasmatic nucleus showed a maximum one day after unilateral retinectomy and was, at all stages studied, two to three times higher in the contralateral than in the ipsilateral nuclear area. In the optic tract and in the superior colliculus the number of degenerating profiles was three times higher in the contralateral than in the ipsilateral area. Retinohypothalamic connections and crossing pattern of retinal fibers were studied light microscopically using impregnation with cobalt sulfide in whole mounts of brains. Most of the optic fibers in the laboratory mouse are crossed crossed (70-80%). A bundle of predominantly crossed optic fibers runs to the suprachiasmatic nucleus.     

Comparative Anatomy of the Leaves of Cephalotaxus (Cephalotaxaceae)

The internal structure and cuticular characters of the leaves of Cephalotaxus were investigated under light microscope and scanning electron microscope. The materials used belong to 9 species, 2 varieties and 1 cultivar. The leaf characters of C. oliveri Mast. are as follows: stomata are amphicyclic and occasionally monocyclic, the stomatal frequency is 120.6/mm², the hypodermis is present, there are a large number of filiform sclereids and a few brachysclereids and astrosclereids in the mesophyll, the cuticular projections on the lower surfaces are indistinct. This species differs from all the other species of Cephalotaxus, in which stomata are amphicyclic only, the stomatal frequency is 47.3-88.1/mm², hypodermis is absent except in C. harringtonia and C. harringtonia cv. ‘Fastigiata’, foliar astrosclereids, hrachysclereids asd fibriform selereids may be present or entirely absent, there are distinct cuticular projections on the lower surface. Based upon the above-mentioned features, the gross morphology as well as the alkaloids. Cephalotaxus may be divided into two sections, namely: Sect. Cephalotaxus and Sect. Pectinatae. In addition, also discussed are following problems: the classification of some species in Sect. Cephalotaxus, the suggested subdivision of Sect. Cephalotaxus into 4 series, and the systematic position of Cephalotaxaceae.     

河豚毒素对金鱼再生的视网膜顶盖投射模式的影响

本文用微量注射荧光染料ＤｉＩ顺行标记的方法,研究了河豚毒素（ＴＴＸ）阻断神经传入活动对金鱼再生的视网膜顶盖投射模式的影响,结果表明,ＴＴＸ处理后再生的视网膜顶盖投射,象正常再生过过程一样,经历了修整的过程,包括再生到顶盖错误区域是视神经纤维的消失和在再生的视神经纤维主干上生长的侧支的消失,与正常再生过程不同是,再生晚期到达顶盖靶区的视神经纤维的终末分支不再相互重叠,而是彼此分离,另外,终末分支数和     

纹外皮层PMLS区反馈投射对初级视皮层神经元反应特性的影响

神经系统中存在大量下行投射,与上行输入一起形成复杂的前馈与反馈回路,调控神经信号的传导和处理,但目前对皮层内反馈投射的功能作用认识还比较薄弱.通过微量注射抑制性神经递质γ-氨基丁酸(γ-aminobutyric acid,GABA),使猫纹外皮层后内侧外上雪氏区(area posteromedial lateral suprasylvian,PMLS)局部可逆性失活,使用胞外记录方法,研究初级视皮层17区神经元反应特性的变化.实验结果显示,PMLS区失活后,17区细胞对运动刺激的反应总体减弱,反应的相对稳定性基本不变,最高发放率/自发之比有所下降.与此同时,细胞的方向选择性指数减小,朝向选择性无显著变化.除少数"双向"反应细胞外,绝大部分细胞的最优方向基本不变.进一步分析发现,细胞对各个方向刺激的反应普遍下降,最优方向上的下降程度最大,是导致方向选择性减弱的主要原因.这些结果表明,PMLS区反馈投射可增强初级视皮层的方向选择性,而对朝向选择性影响有限.这一作用特点体现了PMLS区在皮层中偏重处理运动视觉信息的功能.     

Pop‐Inference: An educational application to evaluate statistical differences among populations

Pop‐Inference is an educational tool designed to help teaching of hypothesis testing using populations. The application allows for the statistical comparison of demographic parameters among populations. Input demographic data are projection matrices or raw demographic data. Randomization tests are used to compare populations. The tests evaluate the hypothesis that demographic parameters differ among groups of individuals more that should be expected from random allocation of individuals to populations. Confidence intervals for demographic parameters are obtained using the bootstrap. Tests may be global or pairwise. In addition to tests on differences, one‐way life table response experiments (LTRE) are available for random and fixed factors. Planned (a priori) comparisons are possible. Power of comparison tests is evaluated by constructing the distribution of the test statistic when the null hypothesis is true and when it is false. The relationship between power and sample size is explored by evaluating differences among populations at increasing population sizes, while keeping vital rates constant.     

基于改进投影寻踪的海洋生态环境综合评价

为了克服现有的海洋环境评价中存在的主观性强、不易处理高维数据的缺陷,提出了基于改进投影寻踪模型的海洋环境评价新方法.该方法利用改进蚁群算法实现了投影寻踪技术,将方案的多维评价指标值投影为一维投影数据,并据投影值大小对样本进行综合评价.工程应用实例表明,该模型易于决策,具有很强的客观性、适用性和可操作性,为海洋生态环境评价提供了新的技术工具.