Test for homogeneity in Hardy–Weinberg normal mixture model

The phenotype of a quantitative trait locus (QTL) is often modeled by a finite mixture of normal distributions. If the QTL effect depends on the number of copies of a specific allele one carries, then the mixture model has three components. In this case, the mixing proportions have a binomial structure according to the Hardy–Weinberg equilibrium. In the search for QTL, a significance test of homogeneity against the Hardy–Weinberg normal mixture model alternative is an important first step. The LOD score method, a likelihood ratio test used in genetics, is a favored choice. However, there is not yet a general theory for the limiting distribution of the likelihood ratio statistic in the presence of unknown variance. This paper derives the limiting distribution of the likelihood ratio statistic, which can be described by the supremum of a quadratic form of a Gaussian process. Further, the result implies that the distribution of the modified likelihood ratio statistic is well approximated by a chi-squared distribution. Simulation results show that the approximation has satisfactory precision for the cases considered. We also give a real-data example.     

Generalized quasi-likelihood

The quasi-score function, as defined by Wedderburn (1974) and McCullagh (1983) and so on, is a linear function of observations. The generalized quasi-score function introduced in this paper is a linear function of some unbiased basis functions, where the unbiased basis functions may be some linear functions of the observations or not, and can be easily constructed by the meaning of the parameters such as mean and median and so on. The generalized quasi-likelihood estimate obtained by such a generalized quasi-score function is consistent and has an asymptotically normal distribution. As a result, the optimum generalized quasi-score is obtained and a method to construct the optimum unbiased basis function is introduced. In order to construct the potential function, a conservative generalized estimating function is defined. By conservative, a potential function for the projected score has many properties of a log-likelihood function. Finally, some examples are given to illustrate the theoretical results. This paper is supported by NNSF project (10371059) of China and Youth Teacher Foundation of Nankai University.     

The analysis of incomplete data using stochastic covariates

In the development of many diseases there are often associated random variables which continuously reflect the progress of a subject towards the final expression of the disease (failure). At any given time these processes, which we call stochastic covariates, may provide information about the current hazard and the remaining time to failure. Likewise, in situations when the specific times of key prior events are not known, such as the time of onset of an occult tumour or the time of infection with HIV-1, it may be possible to identify a stochastic covariate which reveals, indirectly, when the event of interest occurred. The analysis of carcinogenicity trials which involve occult tumours is usually based on the time of death or sacrifice and an indicator of tumour presence for each animal in the experiment. However, the size of an occult tumour observed at the endpoint represents data concerning tumour development which may convey additional information concerning both the tumour incidence rate and the rate of death to which tumour-bearing animals are subject. We develop a stochastic model for tumour growth and suggest different ways in which the effect of this growth on the hazard of failure might be modelled. Using a combined model for tumour growth and additive competing risks of death, we show that if this tumour size information is used, assumptions concerning tumour lethality, the context of observation or multiple sacrifice times are no longer necessary in order to estimate the tumour incidence rate. Parametric estimation based on the method of maximum likelihood is outlined and is applied to simulated data from the combined model. The results of this limited study confirm that use of the stochastic covariate tumour size results in more precise estimation of the incidence rate for occult tumours.     

也论"五四"的主题

“五四”的主题是政治挤压下的启蒙。“五四”整个发展过程中启蒙始终不能完全脱离政治。“五四”落潮,并不是“救亡压倒启蒙”,而是启蒙自身发展和实现现代民族国家必然的客观要求。“五四”启蒙运动是不彻底的,这有其发展的历史性和客观性。因此不能脱离政治孤立地看待启蒙。     

《金锁记》改写的背后

《金锁记》是张爱玲作品中唯一一篇充满斗争激越、呼应“五四”主题的文章。改写后的《怨女》则成为超越时代局限 ,走向人性深处 ,带有普泛性和恒定性主题的文章。在张爱玲的文学趣味向传统复归的背后 ,是作者对“五四”文学的反思 ,以及对中国文艺的表现方式、表现题材的寻求。     

“醒过来的人的真声音”——试论五四新文学早期小说中的爱情表达

五四新文学早期,大量的青年作家在小说创作中关注爱情主题,试图探索爱情中情感与欲望的新关系,主要的区别在于对欲望的态度,大致可以分为三种无助的精神逃避,扭曲的欲望表达和真实的欲望书写.文章阐述这三种思考与表达,分析这三种表达所内蕴的作家的思想意识,并由此指出作家们的总体追求的意义所在.     

N-硝基-N-氨基(取代)甲酰-2,4,6-三氯苯氨类化合物的合成

合成了两种新型兼有植物生长调节剂和除草剂功效的N硝基 -N -氨基 (取代 )甲酰 - 2 ,4 ,6 -三氯苯氨类化合物 ,并经元素分析、红外光谱等证实了它们的结构 .     

五四时期中西文化调和论的互动--兼论五四时期中国文化调和论兴起的外在刺激因素

五四时期 ,欧洲与亚洲之间、亚洲各国家之间的思想文化交流进入了一个新时期。当时 ,调和东西文化是欧洲和亚洲许多学者的共同期待。在亚洲 ,反应最强烈的是印度、日本和中国。印度和日本学者的呼应大大刺激了中国思想界 ,促使部分中国学者极力想找到中国在世界文化建设中的位置 ,而欧洲思想界的波动 ,则成为中国文化调和论者有力的舆论支持。     

高羊茅愈伤组织的诱导与内源激素含量研究

该利用高羊茅种子的离体成熟胚作体植体接种到2，4-D浓度梯度的培养基上进行了愈伤组织诱导，发现2.5mg/L2,4-D是愈伤组织的最佳诱导生长激素，同时利用反相高效液相色谱法测定了愈伤组织和相应的黄化种子苗中的内源激素赤霉酸（GA3），玉米素（ZT），吲哚乙酸（IAA），脱落酸（ABA），吲哚丁酸（IBA）的含量，发现胚性愈伤组织的内源激素（EC）比非胚性愈伤组织（NEC）总含量要高，各种激素在两种愈伤组织与黄化种子苗中的比例也与献报道的相似。     

Stochastic Modelling of Times to Temperature for Furnaces Supplying Titanium Blooms to a Rolling Mill at TIMET

In conjunction with TIMET at Waunarlwydd (Swansea, UK) a model has been developed that will optimise the scheduling of various blooms to their eight furnaces so as to minimise the time taken to roll these blooms into the finished mill products. This production scheduling model requires reliable data on times taken for the various furnaces that heat the slabs and blooms to reach the temperatures required for rolling. These times to temperature are stochastic in nature and this paper identifies the distributional form for these times using the generalised F distribution as a modelling framework. The times to temperature were found to be similarly distributed over all furnaces. The identified distributional forms were incorporated into the scheduling model to optimise a particular campaign that was run at TIMET Swansea. Amongst other conclusion it was found that, compared to the actual campaign, the model produced a schedule that reduced the makespan by some 35%.