A comparison of updating processes in children good or poor in arithmetic word problem-solving

This study examines the updating ability of poor or good problem solvers. Seventy-eight fourth-graders, 43 good and 35 poor arithmetic word problem-solvers, performed the Updating Test used in Palladino et al. [Palladino, P., Cornoldi, C., De Beni, R., and Pazzaglia F. (2002). Working memory and updating processes in reading comprehension. Memory and Cognition, 29, 344–354.]. The participants listened to wordlists, each comprising 12 words referring to objects or animals of different sizes. At the end of each list participants were asked to recall the 3 or 5 words denoting the smallest objects/animals in the list. Results show that poor problem-solvers recalled fewer correct words and made more intrusion errors (recall of non-target words) than good problem-solvers. Results support the hypothesis that the ability to select and update relevant, and suppress irrelevant information, is related to problem-solving, even when the influence of reading comprehension is controlled for. With reference to Baddeley's, and other recent WM models [Miyake, A., and Shah, P. (Eds.), (1999). Models of working memory: Mechanisms of active maintenance and executive control. New York: Cambridge University Press.], our results point to the idea that problem-solving relies on the central executive for processing and updating information contained in the problems.     

人类常见遗传性疾病的遗传方式、特征表现及防治方法

人类常见遗传性疾病有染色体遗传、单基因遗传病和多基因遗传病等三种方式,人类常见遗传性疾病具有先天性、家族性、终生性、发病率高等四大特证．本文通过对人类常见遗传性疾病的遗传方式和特征进行分析。就如何防治人类常见遗传性疾病提出了一些具体措施．     

Genetic variation in alkaloid accumulation in leaves of Nicotiana

Alkaloids are plant secondary metabolites that are widely distributed in Nicotiana species and contribute greatly to the quality of tobacco leaves. Some alkaloids, such as nornicotine and myosmine, have adverse effects on human health. To reduce the content of harmful alkaloids in tobacco leaves through conventional breeding, a genetic study of the alkaloid variation among different genotypes is required. In this study, alkaloid profiles in leaves of five Nicotiana tabacum cultivars and Nicotiana tomentosiformis were investigated. Six alkaloids were identified from all six genotypes via gas chromatograph-mass spectrometry (GC-MS). Significant differences in alkaloid content were observed both among different leaf positions and among cultivars. The contents of nornicotine and myosmine were positively and significantly correlated (R ²=0.881), and were also separated from those of other alkaloids by clustering. Thus, the genotype plays a major role in alkaloid accumulation, indicating a high potential for manipulation of alkaloid content through traditional breeding.     

改进遗传算法在文本聚类中的应用研究

分析了K均值聚类算法（K-means）存在的不足和改进遗传算法的全局优化能力,提出一种基于改进遗传算法的文本聚类方法,该方法将原始文档转化成用向量空间模型来描述的文本向量,首先随机产生若干个文档向量作为初始聚类中心形成遗传算法的染色体种群,经过改进遗传算法的选择、交叉、变异进化运算,得到较为优化的K均值聚类算法的初始聚类中心。实验表明该算法文本聚类提高了查准率和查全率,算法的高效性也得到了验证。     

基于遗传算法的PID控制器参数优化研究

针对PID控制器在不同的应用系统,需要动态调整PID控制参数的问题,提出了基于遗传算法的PID自适应参数优化方案。该方案通过将PID控制器产生的误差作为目标函数,利用遗传算法实现对PID控制器参数的自动调整。为了提高参数的优化效率,文章通过对交叉算子和变异算子的自适应处理,提高了PID控制器的性能。实验测试表明,文章设计的PID参数优化策略比普通的基于遗传算法优化策略效率平均高14.7%。     

Comprehensive screening and selection of okra (Abelmoschus esculentus) germplasm for salinity tolerance at the seedling stage and during plant ontogeny

The okra germplasm was screened for salinity tolerance at the seedling stage and during plant ontogeny. Substantial variation existed in okra for salinity tolerance at the seedling stage. An 80 mmol/L NaCl concentration was suitable for discriminating tolerant and non-tolerant okra genotypes. The pooled ranking of the genotypes, based on individual rankings for each trait (root and shoot length, germination percentage, and relative Na⁺ and K⁺) in individual NaCl concentrations, was effective for selecting tolerant genotypes. Genotypes selected at the seedling stage maintained their tolerance to NaCl during plant ontogeny, suggesting that screening of the germplasm entries and advanced breeding materials for salt tolerance at the seedling stage is effective. Among 39 okra genotypes, five were identified as the most tolerant genotypes and showed potential for use in breeding programs that focus on the development of salt-tolerant, high-yield okra cultivars.     

Application of biomonitoring and support vector machine in water quality assessment

The behavior of schools of zebrafish (Danio rerio) was studied in acute toxicity environments. Behavioral features were extracted and a method for water quality assessment using support vector machine (SVM) was developed. The behavioral parameters of fish were recorded and analyzed during one hour in an environment of a 24-h half-lethal concentration (LC₅₀) of a pollutant. The data were used to develop a method to evaluate water quality, so as to give an early indication of toxicity. Four kinds of metal ions (Cu²⁺, Hg²⁺, Cr⁶⁺, and Cd²⁺) were used for toxicity testing. To enhance the efficiency and accuracy of assessment, a method combining SVM and a genetic algorithm (GA) was used. The results showed that the average prediction accuracy of the method was over 80% and the time cost was acceptable. The method gave satisfactory results for a variety of metal pollutants, demonstrating that this is an effective approach to the classification of water quality.     

Multiobjective optimization and multivariable control of the beer fermentation process with the use of evolutionary algorithms

This paper describes empirical research on the model, optimization and supervisory control of beer fermentation. Conditions in the laboratory were made as similar as possible to brewery industry conditions. Since mathematical models that consider realistic industrial conditions were not available, a new mathematical model design involving industrial conditions was first developed. Batch fermentations are multiobjective dynamic processes that must be guided along optimal paths to obtain good results. The paper describes a direct way to apply a Pareto set approach with multiobjective evolutionary algorithms (MOEAs). Successful finding of optimal ways to drive these processes were reported. Once obtained, the mathematical fermentation model was used to optimize the fermentation process by using an intelligent control based on certain rules.     

黑白花奶牛泌乳曲线参数的方差组份和遗传特性分析

本文根据北京黑白花奶牛860个有完整记录的泌乳期资料,利用wood模型进行了泌乳曲线参数估计,并通过最小二乘法对估计结果进行了方差分析和相关性分析,估计了曲线参数的遗传力、遗传相关(γ_A)、表型相关(γ_P)和环境相关(γ_E)。方差分析表明,父畜和胎次对产奶量(MY)、估计产奶量(EMY)、参数a、c、高峰月份(MPY)和高峰月产奶量(PY)有极显著影响(P<0.01),对持久力有显著影响(P<0.05);分场对b和上述的所有参数均有显著影响(P<0. 01);产犊年份对MY、EMY、a、c和PY有极显著影响(P<0.01)。遗传力(h~2)估计结果为:MY、EMY、a和PY的h~2幅度在0.231—0.271之间;c和PYM的h~2分别为0.183±0.093和0.167±0.089;持久力的h~2为0.115±0.076。相关分析结果表明,PY与MY有强相关(γ_A=0.721,γ_p=0.812,γ_E=0.766)。与b、c均有正相关(γ_A、γ_P和γ_E的幅度为0.355—0.437)。MY与a有正相关(γ_A=o.335,γ_P=0.531,γ_E=0.600)与b、MPY有正相关(γ_A分别为0.348和0.406)与c有负遗传相关(γ_A=—0.370)。持久力与a、b、c以及PY均有负相关、与MPY有正相关。     

小麦生理性状的遗传变异及其与产量的关系研究

利用20个品种(系)探讨了小麦部分生理性状的遗传变异及其与产量的关系.结果表明,除生殖生长期外,其余性状在小麦基因型间均存在显著的遗传差异.生物学产量、叶绿素含量、营养生长期、生殖生长期与营养生长期之比与产量相关显著,且遗传力较高,可作为产量选择的间接指标.高产品种在经济系数、生物学产量、叶绿素含量、叶面积等性状上存在优势,在干物质积累上具有灌浆速度快的特点.