Genetic estimations for body size characters, development period and development rate in a coccinelid beetle,Harmonia axyridis

Heritabilities and genetic correlations for body size characters and development period in a coccinellid beetle,Harmonia axyridis were estimated by a sib-analysis experiment. Positive genetic correlations were detected between size characters and development rate. If this is upheld in the field, genetic variation would be eliminated, as the loci affecting the characters are supposed to be fixed. However, the results indicated moderate heritabilities for all characters. Possible explanations for the results are discussed.     

Stories in Decisions: How At-Risk Individuals Decide to Request Predictive Testing for Huntington Disease

Huntington Disease (HD) is a hereditary neurological disease that typically occurs in mid-life. There is no prevention or cure, but persons at risk may request predictive genetic testing to learn whether or not they will develop the disease later in life. Many studies describe why such persons request this knowledge. Few consider how people actually make this novel decision. Drawing on in-depth interviews with sixteen test candidates, this article differentiates three types of stories about—as well as embedded in—the experience of deciding. Each type of story sheds a different light on the meaning and experience of making this decision. Stories of having to know reveal that decision-making may be experienced as a self-evident act while stories of evolving toward it feature an incremental process of weighing up the implications. Stories of taking the decision feature a pivotal point which involves the narrator in seeing anew the opportunity to make a choice. Emphasizing previously neglected temporal, biographical and phenomenological dimensions of decision-making, this typology underscores the relevance of narrative in complex processes of decision-making. It also illustrates the inadequacy of understanding decision-making purely through the lens of rational choice.     

幻方的遗传算法构造初探

首先介绍遗传算法,并针对一个古老的数学问题——幻方提出了一种基于遗传算法的幻方构造新方法.     

粒子群优化算法及其与遗传算法的比较

粒子群优化算法是根据鸟群觅食过程中的迁徙和群集模型而提出的用于解决优化问题。该文讨论粒子群优化算法的基本原理和实现步骤,分析了该算法中各参数的设置。通过一个测试函数,对粒子群优化算法与遗传算法进行了比较,结果表明粒子群优化算法在找寻最优解效率上好于遗传算法。     

Deme formation in gall-making aphidsAdelges japonicus (Homoptera: Adelgidae)

The deme formation hypothesis in herbivorous insects states that herbivores differentiate genetically into small demes, each specialized in the idiosyncratic traits of individual plants. We examined this hypothesis in gall-forming aphids,Adelges japonicus, by reciprocal transfers of aphids among three susceptible clones ofPicea jezoensis standing in proximity. Performance of aphids transferred to their natal clone was compared with that of aphids transferred to other novel clones. ANCOVA showed no significant donor (source of aphids) by receptor (recipient of aphids) interactions for both total aphid performance on the host tree over a life cycle and its three subdivisions(q ₁,q ₂ andq ₃). In addition, the total performance on the natal clone was lowest among those in the three clones, which was explicitly against the prediction from the local adaptation. In contrast, there were significant receptor effects onq ₁ (fecundity of gallicolae multiplied by survivorship of fundatrices while feeding on needles) andq ₃ (fecundity of fundatrices multiplied by survivorship of gallicolae before emergence from the galls), suggesting genetic differences in resistance among clones. The two-fold difference inq ₃ among clones was due to different gall size, which was highly correlated with the number of gallicolae that emerged from the gall. The two-fold difference inq ₁ seemed to be caused by different survivorship of larval fundatrices while feeding on needles.     

基因工程技术及其在林木培育中的应用

概述了基因工程在国内外林木培育中的应用现状及发展趋势 ,综述了我国十多年来林木在抗虫、抗病、抗逆境、品质改良、育性等基因工程的研究与应用研究取得的一些进展及今后的发展方向。     

一种基于RCPT码的渐进图像传输方法

将等级树中的集分割编码器输出的码流分组,根据输出的分组数据对重建图像重要性的不同,传输前采用纠错能力不同的RCPT码保护。在总的码率限制下,采用遗传算法从有限码率集中选择每组数据的RCPT码码率,使接收端恢复的图像失真最小。将等误差保护码率作为遗传算法的初始种群,减少了最优码率集的搜索时间。在二进制对称信道上的仿真结果表明,该渐进图像传输方法实现简单,在高误码率信道条件下恢复图像仍能得到很高的峰值信噪比。     

Computational Forecasting of Wavelet-converted Monthly Sunspot Numbers

Monthly average sunspot numbers follow irregular cycles with complex nonlinear dynamics. Statistical linear models constructed to forecast them are therefore inappropriate, while nonlinear models produce solutions sensitive to initial conditions. Two computational techniques - neural networks and genetic programming - that have their advantages are applied instead to the monthly numbers and their wavelet-transformed and wavelet-denoised series. The objective is to determine if modeling wavelet-conversions produces better forecasts than those from modeling series' observed values. Because sunspot numbers are indicators of geomagnetic activity their forecast is important. Geomagnetic storms endanger satellites and disrupt communications and power systems on Earth.     

Bayesian incorporation of repeated measurements in logistic discrimination

A common problem in medical statistics is the discrimination between two groups on the basis of diagnostic information. Information on patient characteristics is used to classify individuals into one of two groups: diseased or disease-free. This classification is often with respect to a particular disease. This discrimination has two probabilistic components: (1) the discrimination is not without error, and (2) in many cases the a priori chance of disease can be estimated. Logistic models (Cox 1970; Anderson 1972) provide methods for incorporating both of these components. The a posteriori probability of disease may be estimated for a patient on the basis of both current measurement of patient characteristics and prior information. The parameters of the logistic model may be estimated on the basis of a calibration trial. In practice, not one but several sets of measurements of one characteristic of the patient may be made on a questionable case. These measurements typically are correlated; they are far from independent. How should these correlated measurements be used? This paper presents a method for incorporating several sets of measurements in the classification of a case.     

Families and donor insemination: the views of semen donors

One of the consequences of donor insemination for the semen donor is that he becomes a member of two families: his own family in which he has a genetic and social connection with his offspring; and the family of the recipient couple, in which he has a genetic connection to the offspring, but usually no social connection with either the offspring or the recipient couple. This article challenges the dominant view that donor insemination as a practice of mainly medical or legal importance by looking at the attitudes of donors to both their own family and the family to which they have contributed their genetic material. Results are presented concerning who donors have told about their donation, who they think should be told, whether they think recipient couples should tell their donor insemination offspring about their conception, and concerning their opinions about factors that are considered in matching donors with recipient fathers.