西北太平洋浮游有孔虫的SSU rDNA序列及其古海洋学意义

研究对采集于西北太平洋冲绳海槽表层水体中的活浮游有孔虫进行DNA分析尝试，获得了西北太平洋浮游有孔虫Pulleniatina obliquiloculata 和Globigerina sp.等的SSU rDNA序列特征，并与南太平洋地区属种的DNA序列进行对比. 结果显示两不同海区P.obliquiloculata个体的SSU rDNA差异与同一个体内不同拷贝序列间差异类似，仅为0.7%—1.2%. 详细比较研究认为，传统微体古生物形态学定义种对西北太平洋与南太平洋的P.obliquiloculata来说具有可靠的分子生物学证据.     

An unusual silver celestial planisphere in the Whipple Museum

An unusual silver celestial planisphere is held in the collection of the Whipple Museum of the History of Science (Wh.1762); little information about this object is recorded in the museum’s documentation. A comparison of this silver example with celestial planispheres printed on paper, coupled with the consideration of other aspects of the lives and work of the cartographers and instrument-makers involved in producing such objects, suggests some possibilities regarding its production. Through this individual case study, I aim to demonstrate that the careful examination of an individual instrument, coupled with an understanding of the class of instruments to which it belongs and the milieu in which it was produced, can result in a deeper understanding of any given artefact, its circumstances of design and manufacture, and its intended use and users.     

有孔虫分子生物学研究进展

传统的微体古生物学研究中,有孔虫是生活于海洋环境中以具有膜状、胶结质或钙质壳为特征的丝网状肉足虫类原生动物.最近对底栖有孔虫rDNA序列的分析研究,揭示了有孔虫还有无壳(裸露)种类以及生活于陆地淡水环境的类型.同时分子系统学研究表明有孔虫位于真核生物系统树的基部,在双滴虫类与绿眼虫类之间.对浮游有孔虫大量基因型及其与环境关系的研究,揭示了传统研究低估了有孔虫的多样性.有孔虫基因型与生物地理分布、海洋环境有关研究表明利用rDNA序列分析识别出的同一物种的不同基因型可以为古环境研究提供更加精确的替代性指标.     

Molecular biological research on Foraminifera

ForaminiferabelongstoSarcodina(Protozoa)andexhibitscytoplasmicorganizationandpseudopdial streamingcharacteristicbroadlyofamoeboidorgan ism[1].Itmainlylivesinthemarineenvironment withamembranous,agglutinatedorcalcareousshell.Asoneofthemostimportantgroupsinmicropaleon tology,Foraminiferahasbeenwidelyusedforthe stratigraphicsubdivision,correlationinpetroleum wellsandforthereconstructionofpaleo environments duringthelastseveraldecades[2,3].Furthermore,sincethe1960swiththestartofDeepSeaDrilling …     

Living planktonic foraminifera from the northwestern Pacific Ocean:SSU rDNA sequences and their paleoceanographic significance

Living planktonic foraminifera(PF)samples from the Okinawa Trough of the northwestern Pacific Ocean were taken for DNA analysis.The SSU rDNA sequences of two PF species,Globigerina sp.and Pulleniatina obliquiloculata collected at Station WP01,were obtained and compared with those from the southwestern Pacific Ocean.Only small differences(<0.7%—1.2% for P. obliquiloculata,and 0.3% for Globigerina sp.)were found between samples from the north-and south-western Pacific Ocean areas and this molecular evidence supported that these micropaleontological species are the same species,which implies that the West Pacific Ocean circulation system influences the planktonic foraminiferal gene communication.     

Mincer–Zarnowitz quantile and expectile regressions for forecast evaluations under aysmmetric loss functions

Forecasts are pervasive in all areas of applications in business and daily life. Hence evaluating the accuracy of a forecast is important for both the generators and consumers of forecasts. There are two aspects in forecast evaluation: (a) measuring the accuracy of past forecasts using some summary statistics, and (b) testing the optimality properties of the forecasts through some diagnostic tests. On measuring the accuracy of a past forecast, this paper illustrates that the summary statistics used should match the loss function that was used to generate the forecast. If there is strong evidence that an asymmetric loss function has been used in the generation of a forecast, then a summary statistic that corresponds to that asymmetric loss function should be used in assessing the accuracy of the forecast instead of the popular root mean square error or mean absolute error. On testing the optimality of the forecasts, it is demonstrated how the quantile regressions set in the prediction–realization framework of Mincer and Zarnowitz (in J. Mincer (Ed.), Economic Forecasts and Expectations: Analysis of Forecasting Behavior and Performance (pp. 14–20), 1969) can be used to recover the unknown parameter that controls the potentially asymmetric loss function used in generating the past forecasts. Finally, the prediction–realization framework is applied to the Federal Reserve's economic growth forecast and forecast sharing in a PC manufacturing supply chain. It is found that the Federal Reserve values overprediction approximately 1.5 times more costly than underprediction. It is also found that the PC manufacturer weighs positive forecast errors (under forecasts) about four times as costly as negative forecast errors (over forecasts).     

Peptide antigens for gamma/delta T cells

γδ T cells express adaptive antigen receptors encoded by rearranging genes. Their diversity is highest in the small region of TCR V–J junctions, especially in the δ chain, which should enable the γδ TCRs to distinguish differences in small epitopes. Indeed, recognition of small molecules, and of an epitope on a larger protein has been reported. Responses to small non-peptides known as phospho-antigens are multi-clonal yet limited to a single γδ T cell subset in humans and non-human primates. Responses to small peptides are multi-clonal or oligo-clonal, include more than one subset of γδ T cells, and occur in rodents and primates. However, less effort has been devoted to investigate the peptide responses. To settle the questions of whether peptides can be ligands for the γδ TCRs, and whether responses to small peptides might occur normally, peptide binding will have to be demonstrated, and natural peptide ligands identified.     

Recessive LAMC3 mutations cause malformations of occipital cortical development

The biological basis for regional and inter-species differences in cerebral cortical morphology is poorly understood. We focused on consanguineous Turkish families with a single affected member with complex bilateral occipital cortical gyration abnormalities. By using whole-exome sequencing, we initially identified a homozygous 2-bp deletion in LAMC3, the laminin γ3 gene, leading to an immediate premature termination codon. In two other affected individuals with nearly identical phenotypes, we identified a homozygous nonsense mutation and a compound heterozygous mutation. In human but not mouse fetal brain, LAMC3 is enriched in postmitotic cortical plate neurons, localizing primarily to the somatodendritic compartment. LAMC3 expression peaks between late gestation and late infancy, paralleling the expression of molecules that are important in dendritogenesis and synapse formation. The discovery of the molecular basis of this unusual occipital malformation furthers our understanding of the complex biology underlying the formation of cortical gyrations.     

Molecular biological research on Foraminifera

As one of the most important groups in micropaleontology, Foraminifera is traditionally described to have a membranous, agglutinated or carbonate shell according to its morphology, which resembles the marine granuloreticuloseans. However, recent molecular analyses on its ribosomal RNA gene have disclosed the existence of the naked, and also freshwater and terrestrial species. Foraminiferal SSU rDNA sequence suggests that this group is positioned at the base of the Eukaryotes phylogenetic trees, between Euglenoida and Diplomonadida. Existence of a large amount of genetic types in planktonic foraminifera suggests an underestimation of the biodiversity for the nearly 50 species in world oceans and their close relationship with the ocean environment, such as bio-geographic distribution and water currents. This provides a more reliable proxy for future paleoenvironmental study.     

管状曲面的奇点

研究管状曲面和它的平行曲面的奇点问题.所谓管状曲面,是沿着E3里一条曲线的双参数空间运动产生的.选定曲线的Frenet向量T作为旋转轴,用不同的方法得到了运动管状曲面的特征.然后,给出管状曲面奇点的一些定理和结果.