A new genus and species of snipe fly (Diptera: Rhagionidae) in Lebanese Cretaceous amber

The rhagionid Lebanoleptis huangi gen. et sp. nov. is described from the Lower Cretaceous amber of Lebanon. It is characterized, illustrated, and compared with the recent and fossil genera having the same particular absence of wing vein M3. Other Mesozoic flies with similar venation and currently attributed to the Rhagionidae are briefly discussed and should be revised.     

Effects of freshwater Synechococcus sp. cyanobacteria pH buffering on CaCO3 precipitation: Implications for CO2 sequestration

In the present study, a mixed-flow steady-state bio-reactor was designed to biomineralize CO₂ as a consequence of photosynthesis from active Synechococcus sp. Dissolved CO₂, generated by constant air bubbling of inorganic and cyanobacteria stock solutions, was the only source of inorganic carbon. The release of hydroxide ion by cyanobacteria from photosynthesis maintained highly alkaline pH conditions. In the presence of Ca²⁺ and carbonate species, this led to calcite supersaturation under steady state conditions. Ca²⁺ remained constant throughout the experiments showing the presence of steady state conditions. Similarly, the Synechococcus sp. biomass concentration remained stable within uncertainty. A gradual pH decrease was observed for the highest Ca²⁺ condition coinciding with the formation of CaCO₃. The high degree of supersaturation, under steady-state conditions, contributed to the stabilization of calcite and maintained a constant driving force for the mineral nucleation and growth. For the highest Ca²⁺ condition a fast crystal growth rate was consistent with rapid calcite precipitation as suggested further by affinity calculations. Although saturation state based kinetic precipitation models cannot accurately reflect the controls on crystal growth kinetics or reliably predict growth mechanisms, the relatively reaction orders obtained from modeling of calcite precipitation rates as function of decreasing carbonate concentration suggest that the precipitation occurred via surface-controlled rate determining reactions. These high reaction orders support in addition the hypothesis that crystal growth proceeded through complex surface controlled mechanisms. In conclusion, the steady state supersaturated conditions generated by a constant cyanobacteria biomass and metabolic activity strongly suggest that these microorganisms could be used for the development of efficient CO₂ sequestration methods in a controlled large-scale environment.     

山西太原早二叠世一种新的莲座蕨目植物及古植物地理学和古环境意义?

报道了山西太原西山煤田早二叠世早期太原组7号煤层煤核中一种具解剖构造的两侧对称的莲座蕨目聚合囊，这是目前为止华夏植物区已知地质时代最早的两侧对称的莲座蕨目聚合囊。经对比研究，将当前标本归入始莲座蕨属Eoangiopteris Mamay，并建立一新种：山西始莲座蕨E.shanxiensis sp. nov.。新种的主要特征：生殖小羽片至少2.6 mm宽，长度不明，中脉具一“C”形维管束。小羽片明显背卷，但没有影响到聚合囊的排列。聚合囊两侧对称，长0.75~1.1 mm，宽0.35~0.55 mm，由8~12枚孢子囊构成，孢子囊侧向相互接触。聚合囊具短而明显的托，由薄壁组织包围着维管组织构成。孢子囊直径150~250 mm，高550~850 mm，纵切面上呈筒状，具明显的实心的顶端。孢子囊面向外的壁在中下部为2~3层细胞厚，在顶端为3~4层细胞厚，细胞近等径，壁较厚；侧壁和面向内的壁1层细胞厚，在孢子囊中下部呈弦向伸长状，在顶端则呈径向伸长状，壁较薄。孢子数量多，可达1 000粒以上，小，近球形，直径8~13 mm，具三缝构造，孢子壁由外壁和周壁构成，外壁光滑，周壁具细颗粒纹饰。讨论了本新种的系统分类位置，很可能属于辉木科。根据欧美植物区和华夏植物区两侧对称的莲座蕨目聚合囊的分布特征探讨了本新种的古植物地理学意义。并结合7号煤层煤核中植物化石的组成特征和一些植物的生态解剖学构造简要探讨了本新种的生活环境特征。     

A Miocene algal assemblage dominated by Pediastrum leonensis n. sp. (Chlorophyceae) from Patagonia, Argentina: paleoenvironmental implications

Taxonomic identification of Pediastrum species in an Early Miocene assemblage from southeast Patagonia, Argentina, is used to assess paleoecological conditions. Pediastrum leonensis n. sp. is described based on unique features of the coenobia morphology. It belongs to the P. kawraiskyi–mustersii–patagonicum complex and has no known living counterpart. This group seems to have a long evolutionary history in the region. P. kawraiskyi and P. mustersii are recorded for the first time in pre-Quaternary deposits and their presence suggests a depositional environment represented by a cold stenothermal lake conditions, indicating a temperate to a cold-temperate climate.     

Late-Quaternary diminution and abundance of prehistoric bison (Bison sp.) in eastern Washington state, U.S.A.

Bison (Bison spp.) occurred in eastern Washington state during the late Quaternary. This area is considered to be peripheral to the center of this taxon's natural range. Bison in the plains east of the Rocky Mountains, the heart of this range, underwent diminution during the late Quaternary, and apparently also did so in other, peripheral areas. A ratio diagram of measurement data derived from eight zooarchaeological collections of bison remains recovered from eastern Washington, in combination with the presence of both sexes and all age classes of individuals, indicate that local bison may have also undergone diminution there. There are, however, a relative paucity of bison remains during the middle Holocene and an apparent 2000-year absence of bison from eastern Washington at this time. As a result, the hypothesis that bison became smaller elsewhere and then immigrated to eastern Washington cannot be falsified. Both the diminution and the fluctuating abundance of bison appear to be responses to forage quality and quantity.     

Gymnospermes s.l. du Jurassique supérieur du massif Manamana,Sud-Ouest de Madagascar: une nouvelle paléoflore gondwanienne

Fossil plants from Upper Jurassic sediments belonging to the Gymnosperms s.l. have been studied in the Manamana massif from the southwestern part of Madagascar. The levels are Upper Oxfordian in age on the basis of the palaeontological content, especially with ammonites. The majority of fossil plants are devoided of organic matter but in some cases collodion peels have been made to present epidermal characters. The cuticle of Brachyphyllum madagascariense nov. sp. has been observed with scanning electron microscope (SEM). This new flora is constituted by Pteridospermales and Coniferales. Fragmentary fronds of Pteridospermales have been collected of Pachypteris sp. A and Pachypteris sp. B. Some epidermal characters are described. Coniferales are represented by leafy stems. The diagnosis of Brachyphyllum madagascariense nov. sp. is given with morphological and epidermal characters. Others conifers have been determined: Brachyphyllum sp. A, Brachyphyllum sp. B, Elatocladus sp., Cupressinocladus sp., Cyparissidium sp.. Araucarites sp. remains are probably isolated fertile scales of a female cone. Complete cones of Conites sp. are also present.Comparisons of the systematic composition are made with other Gondwana floras of the same age from Antarctica, South America, Madagascar, India, South Africa, New Zealand and Australia. This flora shows xerophytic adaptations. With the Filicales described by Appert (1973a, b) from the same localities, it is now the most diverse flora from the Upper Jurassic of Madagascar, despite the lack of Cycadales, Bennettitales and Angiosperms.     

A new Burmese amber hawker dragonfly helps to redefine the position of the aeshnopteran family Burmaeshnidae (Odonata: Anisoptera: Aeshnoidea)

The new genus and species Angustaeshna magnifica of Burmaeshnidae is described on the basis of a new fossil from Burmese amber. The genus Cretaeshna from the same amber is transferred from the Telephlebiidae into the Burmaeshnidae. We redefine this last family, no longer considered as the sister group of the Late Cretaceous Enigmaeshnidae, but as putative sister group of the Telephlebiidae in the Aeshnoidea. No known fossil belongs to the Telephlebiidae.     

利用多层薄层贴壁光生物反应器室外培养螺旋藻的研究

设计开发一套新型多层薄层贴壁光生物反应器装置,利用其在室外进行螺旋藻(Spirulina sp.)的高密度培养,对适合螺旋藻的工业贴壁介质材料及光稀释倍数进行初步考察和评价。实验结果表明:附着在超细纤维毛巾上的螺旋藻生物量产率(30~60 g/(m~2·d))要高于附着在植绒材料上的螺旋藻生物量产率(10~40 g/(m~2·d));在实验期间,当光稀释倍数达到10×时,螺旋藻的生物量产率可达到45~60 g/(m~2·d),明显高于2.5×及5×光稀释倍数下的生物量产率;连续培养8 d的螺旋藻平均生物量产率达到30.3 g/(m~2·d),且其营养成分与传统液体培养的螺旋藻营养成分一致。上述结果为该反应器的规模化应用提供支持。     

绒螯蟹凝集素的红细胞凝集活性分析

利用血凝试验及糖抑制试验测定一种绒螯蟹的血清及肌肉提取液的凝血活性及糖抑制专一性,同时进行热稳定性、pH及Ca^2 影响试验。结果显示：血清只能凝集9种红细胞,肌肉提取液能凝集12种红细胞。血清对鹌鹁红细胞的凝集可被乳糖、D-甘露糖、D-果糖、D-半乳糖4种糖所抑制,最小抑制浓度均为200mmol／L,其凝集活性均依赖于Ca^2 ,在pH为6．0～7.0范围内较稳定,经50℃保温10min后活性完全消失。肌肉提取液只被D-甘露糖抑制,在pH为4．0～10．0、温度为4℃～90℃范围内均具活性,说明有很强的耐热性,其凝集活性不依赖于Ca。以上结果表明：血清与肌肉提取液均含有凝集素,且凝集素的种类不同。     

苹果果实轮纹病及其防治

果实轮纹病的病原菌主要是苹果轮纹病菌(Botryosphaeria berengeriana贝伦格葡萄座腔菌梨生专化型和B.berengerana f.sp.piricola贝伦格葡萄座腔菌),苹果果实轮纹病是目前危害最大的果实病害之一。本文综述了苹果果实轮纹病的发生机制及其防治方法。