Sample records for autogeny

  1. Characteristics and mechanism of low permeability beach-bar sandstone reservoir of Es4 in Dongying sag

    Institute of Scientific and Technical Information of China (English)

    WANG Hua-ai; ZHONG Jian-hua; ZHONG Fu-ping; NIU Yong-bin; WANG Pei-jun


    Core and cast sections observation and description, and logging, scanning electron microscope and core lab analysis data etc. Were applied to the present research of the characteristics and mechanism of low permeability beach-bar sandstone reservoir of Es4 in Dongying sag. The results indicated the reservoir has the characteristics of middle-low pores, low-permeability, low compo-sitional and structural maturity, and thin throat. The low-permeability is mainly due to sedimentation (fine particles and argillaceous inter beds) and diagenesis (compaction, cementation, and dissolution). The cementation reduced the physical property of the reser-voir mainly by carbonate cementation, quartz autogeny and enragement, and autogeny clay. Clay minerals usually jam the pores by filling holes, close-fitting the wall of hole, bridging, wrapping grains, and separate attaching the pores and so on. The dissolution is insufficient so as not to improve the porosity and permeability of the reservoir obviously. So it is also an important factor of form-ing low-permeability reservoir.

  2. Distributional Feature of Detrital Minerais in the Superficial Sediment of South Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    王红霞; 林振宏; 郭玉贵


    The composition of detrital minerals with grades of 0.063 - 0.25 mm in the superficial sediment of South Yellow Sea is mainly studied in the paper. The research result shows that the minerals can be divided into more than fifty sorts. The light minerals are mainly feldspar, quartz, mica, etc. The heavy minerals are mainly composed of amphibole, epidote, mica, autogeny pyrite, magnetite, hematite, garnet,zircon and so on, which mainly distribute in the sediments of silty clay and lutaceous silt. According to the content and distribution of the main minerals, the research area isdivided into five miteral combination provinces. The assembled types of minerals in every province have close relationship with its hydrodynamic conditions and sedimentary environment. And the sorts of detrital minerals also show that the detrital substances in the sedimentary areas mainly originate from the drainage areas of rivers,bedrock weathering, and transformed sediment, etc.

  3. Multiple factors contribute to anautogenous reproduction by the mosquito Aedes aegypti. (United States)

    Gulia-Nuss, Monika; Elliot, Anne; Brown, Mark R; Strand, Michael R


    Aedes aegypti is an anautogenous mosquito that must blood feed on a vertebrate host to produce and lay a clutch of eggs. The rockpool mosquito, Georgecraigius atropalpus, is related to A. aegypti but is a facultatively autogenous species that produces its first clutch of eggs shortly after emerging without blood feeding. Consumption of a blood meal by A. aegypti triggers the release of ovary ecdysteroidogenic hormone (OEH) and insulin-like peptide 3 (ILP3) from the brain, which stimulate egg formation. OEH and ILP3 also stimulate egg formation in G. atropalpus but are released at eclosion independently of blood feeding. These results collectively suggest that blood meal dependent release of OEH and ILP3 is one factor that prevents A. aegypti from reproducing autogenously. Here, we examined two other factors that potentially inhibit autogeny in A. aegypti: teneral nutrient reserves and the ability of OEH and ILP3 to stimulate egg formation in the absence of blood feeding. Measures of nutrient reserves showed that newly emerged A. aegypti females had similar wet weights but significantly lower protein and glycogen reserves than G. atropalpus females when larvae were reared under identical conditions. OEH stimulated non-blood fed A. aegypti females to produce ecdysteroid hormone and package yolk into oocytes more strongly than ILP3. OEH also reduced host seeking and blood feeding behavior, yet females produced few mature eggs. Overall, our results indicate that multiple factors prevent A. aegypti from reproducing autogenously.

  4. Asymmetric introgression between sympatric molestus and pipiens forms of Culex pipiens (Diptera: Culicidae in the Comporta region, Portugal

    Directory of Open Access Journals (Sweden)

    Côrte-Real Ana R


    Full Text Available Abstract Background Culex pipiens L. is the most widespread mosquito vector in temperate regions. This species consists of two forms, denoted molestus and pipiens, that exhibit important behavioural and physiological differences. The evolutionary relationships and taxonomic status of these forms remain unclear. In northern European latitudes molestus and pipiens populations occupy different habitats (underground vs. aboveground, a separation that most likely promotes genetic isolation between forms. However, the same does not hold in southern Europe where both forms occur aboveground in sympatry. In these southern habitats, the extent of hybridisation and its impact on the extent of genetic divergence between forms under sympatric conditions has not been clarified. For this purpose, we have used phenotypic and genetic data to characterise Cx. pipiens collected aboveground in Portugal. Our aims were to determine levels of genetic differentiation and the degree of hybridisation between forms occurring in sympatry, and to relate these with both evolutionary and epidemiological tenets of this biological group. Results Autogeny and stenogamy was evaluated in the F1 progeny of 145 individual Cx. pipiens females. Bayesian clustering analysis based on the genotypes of 13 microsatellites revealed two distinct genetic clusters that were highly correlated with the alternative traits that define pipiens and molestus. Admixture analysis yielded hybrid rate estimates of 8-10%. Higher proportions of admixture were observed in pipiens individuals suggesting that more molestus genes are being introgressed into the pipiens form than the opposite. Conclusion Both physiological/behavioural and genetic data provide evidence for the sympatric occurrence of molestus and pipiens forms of Cx. pipiens in the study area. In spite of the significant genetic differentiation between forms, hybridisation occurs at considerable levels. The observed pattern of asymmetric

  5. Experimental study of repairing mandibular bone defect with ADSCs/β-TCP and Platelet-rich fibrin by tissue engineering%复合ADSCs/β-TCP组织工程骨与PRF修复下颌骨缺损的实验研究

    Institute of Scientific and Technical Information of China (English)

    杨世茂; 王明国; 李静; 刘金盼


    Objective: To study the effects of adipose tissue-derived stem cells/β-tricalcium phophate( ADSCs/β-TCP) and Platelet-rich fibrin(PRF) in mandibular defect repair. Methods: Autogenious ADSCs were cultured and PRF was pripared from 27 New Zealand white rabbits. The animals were divided randomly into 3 groups according to a randomized controlled animal experiment; A,B and C with 9 in each group. Bone defect model was made in bilateral mandibulars of each rabbit. β-TCP, ADSCs/β-TCP and ADSCs/β-TCP/PRF were transplanted into the bilateral defects in group A,B and C respectively. 3 rabbits of each group were killed 2, 4,and 8 weeks after operation respectively, and the healing of the defects was observed by gross observation, X-ray and histological examination. Results: The osteogenesis in group C was significantly better than that in group A and B at 2, 4 and 8 weeks ( P 0. 05). Conclusion; The compound of ADSCs/p-TCP/ PRF can improve bone generation in mandibular defect.%目的:探讨脂肪干细胞/β-磷酸三钙(ADSCs/β-TCP)组织工程骨复合富血小板纤维蛋白(PRF)在修复下颌骨缺损中的作用.方法:新西兰大白兔27只,采用随机对照动物实验,随机分为3组,每组9只,培养家兔自体ADSCs,制备自体PRF.在每只兔子的双侧下颌骨制备下颌骨缺损模型.A组:将单纯的β-磷酸三钙(β-TCP)植入双侧下颌骨缺损区,B组:将ADSCs/[β-TCP植入双侧下颌骨缺损区,C组:将ADSCs/β-TCP与PRF植入双侧下颌骨缺损区.分别于术后2、4、8周分别处死9只大白兔,并通过大体观察、X线片、以及组织切片观察下颌骨缺损的修复情况.结果:C组在2、4、8周3个时间点的成骨情况明显优于其他2组(P0.05).结论:ADSCs/β-TCP复合物与PRF联合应用可促进下颌骨缺损的修复.