An organic junction between the vein and membrane of the dragonfly wing

A dragonfly wing consists of membranes and both longitudinal and cross veins. We observed the microstructure cross-section at several locations in the dragonfly wing using environmental scanning electron microscopy (ESEM). The organic nature of the junction between the vein and the membrane was clearly identifiable. The membrane was divided into two layers, the upper epidermis and the lower epidermis. These layers extend around the sandwich structure vein, and combine with the adjacent membrane at a symmetrical location along the vein. Thus, we defined this as an organic junction between the vein and the membranes. The organic junction is able to form a tight corrugation angle, which dramatically increases both the warping rigidity and the strength of the wing, but not the torsional rigidity. The torsional deformation is primarily controlled by the microstructure of the longitudinal veins, and is based on the relative rotation angle between the epidermal layer and the inner layer of the vein that forms the zigzag section.     

Zircon U-Pb ages of granites at Changba and Huangzhuguan in western Qinling and implications for source nature

Mesozoic granitoids are widespread in the Qinling-Dabie-Sulu orogenic belt. Precise U-Pb dating on these granitoids can reveal the evolution of the continental collision orogen and thus provide information on the nature of magma sources. This study presents zircon LA-ICP-MS U-Pb dating and whole-rock geochemical analyses for two intrusions at Changba and Huangzhuguan in western Qinling. Zircon U-Pb ages for central and marginal phases of the Huangzhuguang intrusion are 214±1 Ma and 213±3 Ma, respectively. Zircons from the Changba intrusion yield a dominant cluster with an U-Pb age of 213±2 Ma. Collectively, these ages are younger than ages of 220 to 240 Ma for ultrahigh-pressure metamorphism due to the continental collision between the South China Block and the North China Block, corresponding to syn-exhumation magmatism. Some inherited zircons occur in the Changba intrusion, yielding a weighted mean of ²⁰⁶Pb/²³⁸U ages at 757±14 Ma. This indicates that the Changba intrusion has the crustal source of mid-Neoproterozoic ages and a tectonic affinity to the South China Block. Geochemically, the two intrusuons are both rich in LILE and LREE but depleted in HFSE and HREE, similar to arc-type igneous rocks. The Huangzhuguang intrusion exhibits linear correlations between SiO₂ and the other major oxides, implying chemical evolution from a cognate magma source. It contains mafic enclaves, suggesting possible mixing of felsic-mafic magmas. The Changba granite is rich in Si and K but poor in Fe and Mg as well as has a high value of Fe*, suggesting strong differentiation of granitic magma. Therefore, the two intrusions were derived from the Late Triassic anatexis of the continental crust of different compositions in the northern margin of South China Block. This process may be coupled with exhumation of the subducted continental crust in the stage of late collision.     

基于主成分分析的县域民生金融发展实证研究——以沭阳县为例

在分析我国县域经济重要性的基础上,构建了县域民生金融发展评价指标体系,并设定模型,运用主成分分析法对县域民生金融发展情况进行实证研究.结果显示,县域金融发展情况良好,呈稳步上升的趋势,并在2011年出现一定幅度的上升拐点,这与江苏省政府的政策推动和支持有较大的关联,人民银行南京分行出台的相关方案也推动了整个辖内民生金融的发展,取得了一定成效,县域民生金融整体呈现良好的发展态势.最后,有针对性地提出了有利于促进县域民生金融又好又快发展的相关政策建议.     

Role of two phosphohexomutase genes in glycogen synthesis in Synechocystis sp. PCC6803

Phosphohexomutases catalyze the interconversion between hexose-6-phosphate and hexose-l-phosphate and play important roles in polysaccharide synthesis. In Synechocystis sp. PCC 6803, sl10726 is predicted to encode PGM （phosphoglucomutase）, slr1334 is predicted to encode a PGM/PMM （phosphomannomutase） bifunction enzyme. In comparison to the wild type, a sllO726-null mutant showed 3.4% PGM activity but 45%-69% glycogen content. Down-regulation of slr1334, an essential gene, by using a copper regulated promoter further decreased the PGM activity in the sllO726：：Kmr PpetE-slr1334 double mutant to 0.3% of the wild type level. However, the glycogen content was not further decreased in parallel. In vitro, recombinant Sl10726 or S1r1334 showed predicted enzyme activities. Our results indicate that a relatively high level of glycogen can be maintained in Synechocystis mutants with low levels of PGM activity. The high PGM activity in the cyanobacterium may be required for turnover of glycogen or synthesis of other polysaccharides or oligosaccharides.     

四变量Oregonator模型的复杂动态

运用中心流形定理和分岔理论讨论了基于Belousov-Zhabotinskii反应体系的被改进的Oregonator模型系统的非线性动态,包括随参数变化时平衡点的类型及稳定性变化。从理论上严格证明了系统存在Hopf分岔,通过考察平衡点的分岔,发现了系统振荡现象产生与消失分别是由于平衡点发生Supercritical Hopf分岔和Subcritical Hopf分岔导致的。并通过相关的数值模拟,验证了理论分析的正确性。     

低浓度颗粒流Boltzmann方程的同伦分析方法解

同伦分析方法(homotopy analysis method, HAM)是求解强非线性问题的有力手段. 针对颗粒流的动理学理论中的非线性微分积分方程——?Boltzmann方程, 采用 HAM方法选取局域Maxwell速度分布函数作为初始猜测解, 得到了低浓度颗粒流的Boltzmann方程的一阶近似解, 与传统的Chapman-Enskog方法得到的一阶近似解表达式的结构一致, 初步显示了HAM方法求解Boltzmann方程的有效性, 为一般Boltzmann方程的HAM方法求解奠定了基础.     

Sr-rich apatite from the Dangzishan leucitite-ijolite xenoliths （Heilongjiang Province）： Mineralogy and mantle-fluid metasomatism

Abundant apatite grains with elevated SrO content were found in leucitite-ijolite xenoliths in the Dangzi Mountain,Heilongjiang Province.Morphological and mineralogical associations,and compositional analysis of the Sr-rich apatite,were carried out using an electron microprobe.Two principal types of apatite were distinguished.One type occurs as short-prismatic crystals with Sr-rich rims,while another type with acicular or finely columnar shapes constitutes Sr-rich apatite element maps and systematic quantitative analysis of apatite revealed great variations in SrO content (0.42%-26.79%).The calculated structural formula of the measured Sr-rich apatite is:(Ca3.15-4.963Sr0.019-1.510Ba0.00-0.030Na0.006-0.108REE0.106-0.153) (P2.84-3.028Si0.009-0.094)O12(F0.675-1.079,Cl0.000-0.256,OH0.084-0.297).Mineralogical textures of apatite implied a replacement mechanism for the Sr-rich apatite.Sr-rich rims of apatite are suggested to have formed after metasomatism (isomorphic replacement) of early fluorapatite in a Sr-,light rare-earth elements (LREE),lithophile light elements (LILE)-and volatile-rich residual melt during late magmatism.However,the acicular apatite probably directly crystallized from a Sr-rich residual melt.The Sr-Nd isotopic composition of the apatite was distinctive from that of leucitite-ijolite and its host rock.These differences,combined with mineralogical features of apatite,imply that Sr-LREE-LILE-volatile-rich components in the residual melt were derived from deep in the asthenosphere,and subsequently were enriched at a late stage in magma evolution.