批量甜玉米低场核磁共振数据的统计分析

以烫漂甜玉米的低场核磁共振数据为例,采用统计分析系统（SAS）得到烫漂温度对甜玉米中水分分布的影响规律,利用SAS批量读入数据并对数据进行多指数模型拟合、主成分分析和偏最小二乘法模型预测,提供了相应的SAS代码.结果表明,当弛豫时间为450~750和50~70 ms时,相应水组分的弛豫强度分数随处理温度的变化而呈现出一定的变化规律;烫漂温度可初步划分为3个温度段,即20~40、50~70和80~100 °C;束缚水含量模型具有较高的预测准确性（决定系数R2=0.974,标准差RMSECV=0.32%）;SAS方法在批量数据处理过程中具有较高分析和处理数据的能力.     

A fast and effective method to perform paternity testing for Wolong giant pandas

Captive populations provide a precious genetic resource for endangered animals and a source of individuals for reintroduction to depleted habitats. Therefore, accuracy in determining paternity is of vital importance for managing captive populations and in selecting representative individuals of known genetic characteristics for release. In this study, we established a fast and effective method to conduct paternity testing for captive giant pandas in the Wolong population. This technique uses two highly poly...     

Magnetic fields at the solar wind termination shock

A transition between the supersonic solar wind and the subsonic heliosheath was observed by Voyager 1, but the expected termination shock was not seen owing to a gap in the telemetry. Here we report observations of the magnetic field structure and dynamics of the termination shock, made by Voyager 2 on 31 August-1 September 2007 at a distance of 83.7 au from the Sun (1 au is the Earth-Sun distance). A single crossing of the shock was expected, with a boundary that was stable on a timescale of several days. But the data reveal a complex, rippled, quasi-perpendicular supercritical magnetohydrodynamic shock of moderate strength undergoing reformation on a scale of a few hours. The observed structure suggests the importance of ionized interstellar atoms ('pickup protons') at the shock.     

The first hominin of Europe

The earliest hominin occupation of Europe is one of the most debated topics in palaeoanthropology. However, the purportedly oldest of the Early Pleistocene sites in Eurasia lack precise age control and contain stone tools rather than human fossil remains. Here we report the discovery of a human mandible associated with an assemblage of Mode 1 lithic tools and faunal remains bearing traces of hominin processing, in stratigraphic level TE9 at the site of the Sima del Elefante, Atapuerca, Spain. Level TE9 has been dated to the Early Pleistocene (approximately 1.2-1.1 Myr), based on a combination of palaeomagnetism, cosmogenic nuclides and biostratigraphy. The Sima del Elefante site thus emerges as the oldest, most accurately dated record of human occupation in Europe, to our knowledge. The study of the human mandible suggests that the first settlement of Western Europe could be related to an early demographic expansion out of Africa. The new evidence, with previous findings in other Atapuerca sites (level TD6 from Gran Dolina), also suggests that a speciation event occurred in this extreme area of the Eurasian continent during the Early Pleistocene, initiating the hominin lineage represented by the TE9 and TD6 hominins.     

Molecular evolution of connective tissue growth factor in Cyprinidae （Teleostei： Cypriniformes）

Connective tissue growth factor （CTGF） plays an important role in regulation of cell growth, differentiation, apoptosis and individual development in animals. The study of sequences variation and molecular evolution of CTGF gene across various species of the cyprinid could be helpful for understanding of speciation and gene divergence in this kind of fish. In this study, 19 novel sequences of CTGF gene were obtained from the representative species of the family Cyprinidae using PCR amplification, cloning and sequencing. Phylogenetic relationships of Cyprinidae were reconstructed by neighbor-joining （NJ）, maximum parsimony （MP）, maximum likelihood （ML） and Bayesian method. Oryzias latipes from the family Cyprinodontidae was assigned to be the outgroup taxon. Leuciscini and Barbini were clustered into the monophyletic lineages, respectively, with the high nodal supports. The estimation of the ratio of non-synonymous to synonymous substitution （dN/dS） for the various branches indicated that there stood the different evolution rates between the Leuciscini and the Barbini. With the ratio of dN/dS of the Leuciscini being lower than that of the Barbini, species within the Barbini were demonstrated to be subjected to the relatively less selection pressure and under the relaxable evolution background. A 6 bp indel （insertion/deletion） was found at the 5＇ end of CTGF gene of Cyprinidae, and this 6 bp deletion only appeared in the Leuciscini, which is a typical characteristic of the Leuciscini and provides evidence for the monophylogeny of the Leuciscini. For the amino acid sequences of CTGF protein, the most variations and indels were distributed in the signal region and IGFBP region of this protein, implying that these variations were correlated with the regulation of the CTGF gene expression and protein activity.     

A Cretaceous terrestrial snake with robust hindlimbs and a sacrum

It has commonly been thought that snakes underwent progressive loss of their limbs by gradual diminution of their use. However, recent developmental and palaeontological discoveries suggest a more complex scenario of limb reduction, still poorly documented in the fossil record. Here we report a fossil snake with a sacrum supporting a pelvic girdle and robust, functional legs outside the ribcage. The new fossil, from the Upper Cretaceous period of Patagonia, fills an important gap in the evolutionary progression towards limblessness because other known fossil snakes with developed hindlimbs, the marine Haasiophis, Pachyrhachis and Eupodophis, lack a sacral region. Phylogenetic analysis shows that the new fossil is the most primitive (basal) snake known and that all other limbed fossil snakes are closer to the more advanced macrostomatan snakes, a group including boas, pythons and colubroids. The new fossil retains several features associated with a subterranean or surface dwelling life that are also present in primitive extant snake lineages, supporting the hypothesis of a terrestrial rather than marine origin of snakes.     

基于翻转课堂的大学计算机基础课程教学模式研究

大学计算机基础课程是一门重要的基础课程,但因当前高等院校存在生源复杂、学生水平参差不齐等问题,实际教学效果不尽如人意。分析了当前大学计算机基础课程改革面临的新挑战,探讨了基于翻转课堂的教学新模式,使学生在通过自主学习完成对知识的深度掌握。通过问卷调查和对比研究,证明该模式在一定程度上提高了学生学习兴趣,有利于知识的吸收,提高了教学质量,获得了较好的教学效果。     

基于丝网印刷技术的电化学酶联免疫吸附

为研究基于丝网印刷技术的电化学酶联免疫吸附(ELISA)的效果,在塑料基板上印刷96孔电极单元,形成标准96孔ELISA检测板,建立电化学检测与ELISA实验的关联,检测板每孔底部为独立电化学单元,由碳电极、对电极和银参比电极组成,形成双面印刷基板,基板通过96×3针式镀金特定连接器连接至恒电位仪。结果表明,96孔三电极电化学丝网印刷电化学阵列作为ELISA检测是可行的,多通道恒电位仪可同时测量8个孔数据。