An Algorithm for the Maximum Likelihood Problem on Evolutionary Trees

We investigate the problem of reconstructing evolutionary trees with maximum likelihood (MLET). In the MLET problem, a set of genetic sequences is given and a feasible solution is sought, consisting of an evolutionary tree (where general nodes correspond to sequences and input sequences occur as leaves) along with assignments for the interior nodes. Due to the difficulty of solving the MLET directly, we consider two restricted versions of the problem: the ancestral maximum likelihood (AML) and the maximum parsimony (MP) problems. If we let d_e denote the number of different characters occurring in two nodes linked by edge e, then the objective function of the AML problem is min ∑_{eσ E(T)} H(d_e/k), where H is the entropy function and k is the length of each sequence. In the MP we consider the objective function min σ_{e∊ E(T)} d_e/k. Both the AML and the MP are NP-hard. We propose a new approach for computing solutions for these problems, based on genetic algorithms.     

Sexual and Reproductive Strategies Among Serbian Gypsies

This paper deals with a full range of sexual and reproductive behaviors among different tribes of Gypsies in Serbia. The examined traits include rates of fertility, mortality, age distribution, education, crime rates, and parental care. In addition, Gypsy traditions of culturally prescribed sexual behavior are also studied. It is found that Gypsy tribes employ different reproductive strategies, ranging from an extreme, for humans, r (reproductive) strategy to a more typical K (parental) strategy. The reasons bringing about these differences come from the Gypsies' readiness to adjust their behavior and reproduction in order to create the most favorable strategy in a given environment. This paper elucidates and contrasts the more typical r-selected Gypsies with a group of K-selected Gypsies living in a Serbian village.     

人类美人尖等4对性状的调查及遗传分析

通过对人类群体美人尖、10指自然相嵌、大拇指弯曲度及酒窝4对性状的调查，并对调查结果进行了统计、分析。结果表明：这些性状是受遗传基因控制的，美人尖对无美人尖为显性；10指自然相嵌中右拇指在上对左拇指在上为显性；没有酒窝为显性，有酒窝为隐性；大拇指不弯为显性，弯曲为隐性。     

Inter- and intra-population variations in diapause attribute of the two-spotted spider mite,Tetranychus urticae Koch, in Japan

Summary Populations of the two-spotted spider mite,Tetranychus urticae Koch collected from various localities and from various host plants in Japan showed wide variations in diapause attribute. Diapause percentages at 18°C/9L15D varied from nearly 100% in the north to 0% in the south-west. At intermediate latitudes the mites showed wide inter-population variations. Populations on herbaceous hosts in vinyl- or glass-houses gave significantly lower incidence of diapause than those on roses and deciduous fruit trees. Presence of winter hosts and better host quality under protected environments seemed to favour non-diapausing mites. The temperature threshold for diapause expression also varied widely among local populations. Northern populations consistently had higher and less variable thresholds than populations at intermediate latitudes with thresholds between 15 and 18°C. Inbred lines derived from a population in Kyoto exhibited a wide variation in diapause percentage at 18°C. These results show that diapause inT. urticae is a quantitative threshold trait and that populations in central Japan consist of a variety of genotypes with different diapause traits. This might provide a genetic source for adaptation to local and temporal variations in environmental conditions.     

Reproduction and egg diapause of the oriental chinch bug,Cavelerius saccharivorus okajima (Heteroptera: Lygaeidae), in the subtropical winter season in relation to its wing polymorphism

Summary Reproduction and egg diapause of the oriental chinch bug,Cavelerius saccharivorus, in the subtropical winter season were investigated in relation to its wing polymorphism. Macropterous females collected from the southern part of Okinawa Is. in the autumn season delayed their oviposition and were less fecund early in the adult life period, but survived much longer than brachypterous females collected from the same locality. The total fecundity was not significantly different between wing morphs. The diapause of eggs laid by brachypters tended to be terminated more easily at a high temperature than that of eggs laid by macropters. This indicated that the eggs laid by macropters were more intense in their diapause than those laid by brachypters. However, irrespective of the parental wing form, diapause showed considerable variation in its intensity within and between clutches.     

Factors and consequences of a non-functional alary polymorphism inPyrrhocoris apterus (Heteroptera: Pyrrhocoridae)

Functional alary polymorphisms have been studied rather extensively in several insect species. This review article deals with factors controlling wing polymorphism in a flightless species,Pyrrhocoris apterus (L.), and discusses its adaptive significance and mechanisms for their persistence under natural conditions. The macropterous morph is determined by a recessive allele whose penetrance depends on photoperiod and temperature. Natural populations of this species contain a small fraction of flightless macropters. The disadvantages of being a macropter (increase of development time, decrease of fecundity) are minimal, while the benefit may consist in the tendency to prereproductive arrest of ovarian development in teneral females. It prevents establishing a second generation which would mostly die during the next winter. The mechanism of alary morph regulation may be an ancestral trait linkingP. apterus with other polymorphic Heteroptera, while its decreased penetrance may be a derivative character. Variation in fitness due to alary morphs is small compared to the one associated with differences in body size. The latter is environmentally determined, and not linked to the genetic basis of wing polymorphism. In the “mosaic” of phenotypes of various size the significance of the genetic macroptery may be close to neutral.     

A multi-objective particle swarm for a flow shop scheduling problem

Flow shop problems as a typical manufacturing challenge have gained wide attention in academic fields. In this paper, we consider a bi-criteria permutation flow shop scheduling problem, where weighted mean completion time and weighted mean tardiness are to be minimized simultaneously. Since a flow shop scheduling problem has been proved to be NP-hard in strong sense, an effective multi-objective particle swarm (MOPS), exploiting a new concept of the Ideal Point and a new approach to specify the superior particle's position vector in the swarm, is designed and used for finding locally Pareto-optimal frontier of the problem. To prove the efficiency of the proposed algorithm, various test problems are solved and the reliability of the proposed algorithm, based on some comparison metrics, is compared with a distinguished multi-objective genetic algorithm, i.e. SPEA-II. The computational results show that the proposed MOPS performs better than the genetic algorithm, especially for the large-sized problems.     

面向成套订单问题的工艺规划与排序的集成研究

本文从工艺规划与排序的集成优化角度研究了成套订单问题^[1],克服了单独研究工艺规划和排序局部优化的局限性.文章中考虑了同一工件内部各道工序之间存在的优先加工限制,以及工件在不同机器上加工需要转移时间和工序间接连加工需要机器调整时间的情况,建立了成套订单问题的集成排序模型,并提出了针对求解大规模问题的基于遗传算法的启发式算法,最后通过一个算例对所研究的集成排序问题和所提出的算法进行了说明,计算结果表明了算法的有效性.     

基于二元产权的共同治理机制研究

二元产权制度安排通过对人力资本要素价值创造潜力的挖掘和释放驱动企业价值高效增长,是知识经济时代理想的产权制度安排。传统公司治理机制不适应于二元产权制度,二元产权制度下的三源价值影响力场决定,治理模式必须由股东单边治理转向要素资本所有者共同治理。共同治理模式蕴含共同决策机制、共同制衡机制、激励引导机制和社会治理补充机制。在这一治理模式下,人力资本投资者、物力资本投资者和债务资本投资者以产权保护为核心目的,通过对决策、制衡、监督和约束等环节的深度参与,从根本上改善了公司治理环境、提高了公司治理效率,成为驱动企业价值的重要制度资源。     

Talking About Genetics: Community Perceptions of the Importance of Biological Inheritance for Determining Child Outcome

As part of a study of community attitudes toward adoption, 82 Canadians responded to questions concerning the importance of biological inheritance for determining child outcome, whether it is important for a person to know a great deal about his or her biological background, and what particular things a person should know about his or her biological background. Substantial support existed for the need to know one's biological background, especially medical history. Reference to scientific studies, genes, and genetics were strongly associated with “very important” responses; but parenting and sociocultural family environment were viewed as mediating the influence of biological inheritance. Implications for adoption practice are considered.