An Approximate EM Algorithm for Nonlinear Mixed Effects Models

In this article, we construct an approximate EM algorithm to estimate the parameters of a nonlinear mixed effects model. The iterative procedure can be viewed as an iterative method of moments procedure for estimating the variance components and an iterative reweighted least squares estimates for estimating the fixed effects. Therefore, it is valid without the normality assumptions on the random components. A computationally simple method of moments estimates of the model parameters are used as the starting values for our iterative procedure. A simulation study was conducted to compare the performances of the proposed procedure with the procedure proposed by Lindstrom and Bates (1990) for some normal models and nonnormal models.     

应用蒙特卡洛方法对黑龙江创业农场水稻单产变化的预测

应用蒙特卡洛方法对创业农场水稻单产进行模拟计算和预测,这样的预测结果较其它方法更接近于实际的结果．     

How to monitor elusive lizards: comparison of capture–recapture methods on giant day geckos (Gekkonidae, Phelsuma madagascariensis grandis) in the Masoala rainforest exhibit, Zurich Zoo

Rapid and reliable estimation of population size is needed for the efficient monitoring of animal populations of conservation concern. Unfortunately, technical advances in this area have not been paralleled in uptake in conservation, which may be due to difficulties in implementation or the lack of general guidelines for application. Here we tested five different methods used to estimate population size [capture–mark–recapture (CMR), finite-mixture models, model averaging of finite-mixture models, accumulation curve methods (ACM), and the line transect method (LT)] using extensive capture–recapture data of the giant day gecko (Gekkonidae, Phelsuma madagascariensis grandis, Gray 1870) at the Masoala rainforest exhibit, Zurich Zoo. When the complete data were analyzed [30 sessions (and 27 sessions for the LT)], all methods except the LT produced similar estimates of population size. The simple ACM gave a small coefficient of variation (CV), but did not cover the most likely value of population size at moderate sampling effort. Nevertheless, the ACM was the only method that showed a reasonable convergence when subsets of data were used. CMR and Pledger models included the reference value in their confidence intervals (CI) after 25 and 30 sessions, respectively. Although model averaging did slightly improve the estimate, the CV was still high for the full dataset. Our method of using subsets of data to test the robustness of estimates is simple to apply and could be adopted more widely in such analyzes to evaluate sensitivity to method of evaluation. In conclusion, simple accumulation methods showed similar efficiency to more complex statistical models, and are likely to be sufficiently precise for most conservation monitoring purposes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Kinetic and Thermodynamic Solubility Values of Some Bioactive Compounds

Thermodynamic solubility is a decisive physicochemical property in drug development. The Chasing Equilibrium method offers an alternative to the classical procedures to measure the solubility of compounds with acid–base properties. The method is fast and yields accurate results. In this work, the solubility of several compounds including acids and bases was determined through the Chasing Equilibrium approach. A study of experimental conditions in terms of sample weight was performed to measure solubilities. The study shows that only a limited range of weights, depending on the nature and solubility of the compounds, is adequate to obtain reliable results.     

小麦高分子量麦谷蛋白亚基的 SDS-PAGE方法

小麦高分子量麦谷蛋白亚基(HMW-GS)与小麦面粉的加工品质密切相关,SDS-PAGE是其常用分离方法。在前人工作的基础上摸索了一套适于分析HMW-GS的SDS-PAGE方法,具有简便、快速、微量、不影响种子萌发出苗、分辨率好、制成干板清晰、不皱缩、易保存等优点,以供有关工作者参考。     

Interactions of the DNA polymerase X from African Swine Fever Virus with the ssDNA. Properties of the total DNA-binding site and the strong DNA-binding subsite

Interactions of the polymerase X from the African Swine Fever Virus with the ssDNA have been studied, using quantitative fluorescence titration and fluorescence resonance energy transfer techniques. The primary DNA-binding subsite of the enzyme, independent of the DNA conformation, is located on the C-terminal domain. Association of the bound DNA with the catalytic N-terminal domain finalizes the engagement of the total DNA-binding site of the enzyme and induces a large topological change in the structure of the bound ssDNA. The free energy of binding includes a conformational transition of the protein. Large positive enthalpy changes accompanying the ASFV pol X-ssDNA association indicate that conformational changes of the complex are induced by the engagement of the N-terminal domain. The enthalpy changes are offset by large entropy changes accompanying the DNA binding to the C-terminal domain and the total DNA-binding site, predominantly resulting from the release of water molecules.     

陈旧标本DNA提取方法

对于自然环境中的或长期保存的动物标本,由于保存环境不良或保存时间过长,DNA提取的难度较大。受标本保存时间和损害程度等因素影响,导致实验结果的不稳定性加强,对于同一标本需要反复实验。为了提高DNA提取效率,节省实验成本,现对陈旧损坏标本的DNA提取方法进行综述。     

Accuracy and precision of gait events derived from motion capture in horses during walk and trot

This study aimed to create an evidence base for detection of stance-phase timings from motion capture in horses. The objective was to compare the accuracy (bias) and precision (SD) for five published algorithms for the detection of hoof-on and hoof-off using force plates as the reference standard.     

用Hela229细胞培养法研究呼吸道肺炎衣原体感染

本文用Ｈｅｌａ２２９细胞培养与单克隆抗体免疫荧光法对９４０例咽拭子及２２４例纤支镜取材标本进行肺炎衣原体分离鉴定。结果正常组、上呼吸道感染组、下呼吸道感染组、肺部肿瘤组的咽拭子标本分离率分别为０％（０／２４８）,２．１３％（１０／４６８）,２．１％（３／１４６）,１．２８％（１／７８）。上呼吸道感染组和下呼吸道感染组的分离率均高于正常组和肺部肿瘤组。前二组与正常组的差异有显著性意义（Ｐ＜０．０５）,与肿瘤组的差异无显著性意义（Ｐ＞０．０５）。下呼吸道感染组、肺部肿瘤组的纤支镜取材分离率分别为１０．９６％（     

大尺度不透水面遥感估算方法比较——以京津唐为例

城市不透水面既是常用的城市化程度指标,也是衡量环境质量的重要指标。采用遥感技术准确提取城市不透水面并分析其空间扩张过程,对生态城市建设具有重要意义。基于Landsat 5 TM影像,采用NDVI二元法和线性光谱分解法,分别提取北京、天津和唐山3个城市不透水面信息,并将不透水面估算结果与近同期的ALOS影像提取结果对比验证。结果表明,线性光谱分解法获取的不透水面结果较好,RMSE为20.6%,能有效提取大范围的不透水面信息。