Phylogenetic position of Dictyostelium inferred from multiple protein data sets

The phylogenetic position of Dictyostelium inferred from 18S rRNA data contradicts that from protein data. Protein trees always show the close affinity of Dictyostelium with animals, fungi, and plants, whereas in 18S rRNA trees the branching of Dictyostelium is placed at a position before the massive radiation of protist groups including the divergence of the three kingdoms. To settle this controversial issue and to determine the correct position of Dictyostelium, we inferred the phylogenetic relationship among Dictyostelium and the three kingdoms Animalia, Fungi, and Plantae by a maximum-likelihood method using 19 different protein data sets. It was shown at the significance level of 1 SE that the branching of Dictyostelium antedates the divergence of Animalia and Fungi, and Plantae is an outgroup of the Animalia-Fungi-Dictyostelium clade.Correspondence to: T. Miyata     

Phylogenetic structure of the extinction and biotic factors explaining differential survival of terrestrial notosuchians at the Cretaceous–Palaeogene crisis

Although the clade Crocodylomorpha is represented by few extant species (Crocodylia), it has a rich fossil record. Hundreds of species, adapted to terrestrial, semi-aquatic and marine environments, have existed over more than 200 million years. Numerous studies have attempted to characterize the factors driving the diversification and extinction events of Crocodylomorpha, resulting in ambiguous and even contradictory conclusions, which points to the need for phylogenetically and temporally smaller-scaled studies. Here, we focus on differential survival at the Cretaceous–Palaeogene (K–Pg) crisis of Notosuchia, a diverse clade of mostly terrestrial Crocodylomorpha that achieved great diversity during the Cretaceous. More precisely, we tested the effect of body size and palaeotemperatures on notosuchian survival probability during the K–Pg crisis as well as the effect of diet on the evolution of their body size. We find that Notosuchia showed an evolutionary trend towards larger body sizes through time, associated with a shift from an omnivorous to a carnivorous diet. This may explain why sebecids were the only notosuchians to survive the K–Pg crisis. We also corroborate the conclusions of previous studies that detected a Lagerstätten effect occurring in the Adamantina Formation (Upper Cretaceous, Brazil, Bauru Group). This work confirms the value of more finely-scaled macroevolutionary studies for understanding the history of a rich and complex group such as Crocodylomorpha.     

西双版纳热带季节雨林的粗死木质残体及其养分元素

对西双版纳热带季节雨林的粗死木质残体及养分元素贮量进行了研究。结果表明,西双版纳热带季节雨林粗死木质残体的贮量为16.2 t·hm^-2,约占地上活体生物量的4%左右。其中枯立木占32.5%,倒木占33.2%,倒木残体占12.6%,大枝占21.7%。本研究的粗死木质残体贮量低于巴西和东南亚的热带雨林,处于全球热带雨林的下限。粗死木质残体的氮、磷、钾、钙、镁5种元素的贮量分别为61.8、3.4、30.4、118.3和16.5 kg·hm^-2。其中倒木所占比例最大,为31.9%～44.8%;枯立木次之（21.5%～28.7%）;倒木残体占10.3%～25.5%;3个径级的大枝占14.4%～28.9%。枯立木的C/N、C/P和N/P要高于倒木、倒木残体和大枝。     

目标教学法在护理教学查房中的应用价值分析

目的:探讨目标教学法在护理教学查房中的临床应用价值,以培养护生的临床思维能力,并且提高实践工作能力。方法:选取我院2014年5月~2014年9月在急诊科实习的护生120人为研究对象,在实习之初,按照随机的原则将其分为观察组与对照组,每组60人。在查房中,观察组实施目标教学法,对照组实施常规护理教学法。实习结束后,调查两组护生对查房时教学与课堂效果的满意程度,记录两组护生病历书写的质量以及在实习结束后,通过考核,统计两组护生的在理论成绩、基础护理成绩、专科护理成绩以及护理综合技能方面的成绩,然后对所得到的数据进行统计,以探讨目标教学法在护理教学查房中的临床应用价值。结果:从查房时教学的满意程度及对课堂效果的满意程度来看,观察组都高于对照组,差异具有统计学意义(P0.05);观察组病历书写优良的人数为48,优良率为80%,高于对照组,差异具有统计学意义(P0.05);观察组护生的理论成绩、基础护理成绩、专科护理成绩及护理综合技能的成绩均高于对照组,差异具有统计学意义(P0.05)。结论:目标教学法是一种科学、合理并且适合时代发展要求的新型教学法,应用于护理教学查房中,能提高护生的主动性,激发护生的学习兴趣,充分发掘其潜能,做到理论与实际的结合,从而提高学习者的自身能力,值得临床推广应用。     

Estimation in independent observer line transect surveys for clustered populations

This paper introduces a framework for animal abundance estimation in independent observer line transect surveys of clustered populations. The framework generalizes an approach given in Chen (1999, Environmental and Ecological Statistics 6, in press) to accommodate heterogeneity in detection caused by cluster size and other covariates. Both parametric and nonparametric estimators for the local effective search widths, given the covariates, can be derived from the framework. A nonparametric estimator based on conditional kernel density estimation is proposed and studied owing to its flexibility in modeling the detection functions. A real data set on harbor porpoise in the North Sea is analyzed.     

南京地区12种常绿阔叶树种冬季抗寒性动态变化

选取南京地区露地引种的12种常绿阔叶树种,借助电导法对其抗寒性进行研究,结果表明:12种常绿树种在2003年与2005年冬季期间,抗寒能力高低排序具有很好的一致性与重复性.12种常绿树种在2005年10月至2006年3月期间随冬季低温诱导进行其抗寒能力呈逐渐增强趋势,其中在1月中旬树种抗寒能力均达到最强,而通常在10月份或3月份期间树种抗寒能力最弱.比较而言,12种常绿阔叶树种对冬季低温条件响应的快慢程度各有差异,其中樟科的香樟(Cinnamomum camphora)、浙江樟(Cinnamomum japonicum)属于低温快速响应型,而冬青科的冬青(Ilex purpurea)、大叶冬青(Ilex latifolia)属于低温滞缓响应型,其余树种为正常响应型.12种常绿阔叶树种试验所得抗寒能力结果与引种地冬季观察结果具有很好的对应性.研究结果可为常绿阔叶树种进一步向较高纬度地区的引种与栽培管理工作提供重要的参考.     

Role of a reaction coordinate in free energy calculations

Abstract

The free energy calculation method emerges as a viable technique for ‘in-silico’ calorimetry. Efficient sampling techniques and the good choice of a reaction path connecting the reactant and the product state enable accurate computations of the free energy differences. We argue that in many cases the thermodynamic integration technique has the lowest variance when the transformation between the reactant and the product state proceeds along the natural path of the studied chemical reaction. We provide examples of free energy calculations for the fragmentation of the charged clusters and the swapping reaction of oligomer formation in proteins that follow a tentative reaction mechanism.     

鼎突多刺蚁脑部组织切片方法初探及其脑部结构

膜翅目昆虫蚂蚁具有明显的多态现象,社会性生活中的分工亦非常明确。而作为蚁科中的鼎突多刺蚁还有着较高的药用保健价值。因此对其神经系统的研究有着重要的生物学意义。但蚂蚁脑部坚硬的外骨骼使得对其的组织学切片有一定难度。本试验即对鼎突多刺蚁的脑部组织切片方法进行了摸索和研究。     

Four new limonoids from the seeds of Chukrasia tabularis A. Juss.

Two new C-15 enolic acyl phragmalin-type limonoid orthoesters (1-2) which possessed a C-15-propionyl phragmalin skeleton and two new mexicanolide-type limonoids (3-4) were isolated from the ethanol extract of seeds of Chukrasia tabularis A. Juss. Their structures were established on the basis of spectroscopic analyses and electronic circular dichroism (ECD) exciton chirality method. Additionally, all of the compounds were screened against three human tumor cell lines MCF-7, SMMC-7721, and U2OS.