The barbs (Barbus spp.) of Lake Tana: a forgotten species flock?

Synopsis All living species occupy an ecological niche, and are positioned within a trophic hierarchy. Extinct organisms presumably held similar behavioral and coevolutionary characteristics in the past, and were susceptible to the same kinds of natural ecological pressures operating today. Paleoecological investigations are limited by the incompleteness of the fossil record, and particularly by a lack of behavioral data that are so fundamental to ecological studies of living communities and habitats. Opportunities to examine the coevolutionary structure of ancient communities from empirical data are extremely rare. One such opportunity is provided by the Lower Cretaceous Santana Formation of north-eastern Brazil, a series of richly fossiliferous strata approximately 110 million years old. Many fossil fishes from the Santana Formation contain identifiable prey, including decapod crustaceans and fishes. A trophic hierarchy of these organisms is reconstructed here, and their ecological relationships are discussed. Comparison is made with a similar fish fauna from the Upper Jurassic Solnhofen Limestone of Germany. Low-level, intermediate and high-level predators are identified in each fauna. Predator-prey relationships in the Santana fauna are strongly hierarchical, and are more focussed at the intermediate predator level than in Solnhofen. Comparison with a model of predator-prey relationships between fishes and benthic fauna of the Baltic Sea (which like the Araripe Basin represents a semi-enclosed environment) suggests that heavy predation on teleosts such asRhacolepis, occupying an intermediate trophic level, may have permitted benthic decapods to proliferate and exclude other benthic organisms. Less intense predation on fishes at the intermediate trophic level would allow their numbers to increase, thereby increasing the intensity of predation on the benthos at the base of the trophic hierarchy.     

鄂东南地区下侏罗统武昌组的双壳类化石

湖北蒲圻车埠和大冶金山店下侏罗统武昌组的双壳类化石可划分为２个组合,武昌组中部Ｑｉｙａｎｇｉａ－Ａｐｓｅｕｄｏｃａｒｄｉｎｉａ组合和武昌组上部Ｈｕｂｅｒｉｃｏｎｃｈａ－Ｋｉｊａ（Ｗｕｃｈａｎｇｅｌｌａ）组合,前者时代为早侏罗世中晚期;后者暂归于早侏罗世最晚期。文中描述２新属１新亚属以及１５新种。     

Vegetation patterns in relation to micro-scale landforms in hilly land regions

Spatial structures of landforms as constants affecting vegetation patterns are discussed based on analyses of hilly land regions, mostly in the vicinity of Sendai, northeast Japan. The lower part of a hillslope is characterized by relatively active processes of soil erosion, landslides and slope failure. It supports a plant community different from that on the upper part of the hillslope. These two parts are termed the lower hillslope and the upper hillslope, respectively. The upper hillslope consists of valley heads with no stream water nor stream channels. Since a valley head is comprised of several micro-scale landform units, an upper hillslope can be subdivided into these landform units. Plant communities vary in their species compositions and structures as well as in some other ecological characteristics paralleling changes in their respective micro-scale landform units. However, the variations in species composition within upper hillslopes are not as extreme as those between the upper and lower hillslopes. xx]Papers presented at the Vth INTECOL Congress at YOKO-hama 1990.     

气压治疗仪联合那屈肝素预防剖宫产术后下肢静脉栓塞的临床研究

摘要 目的：探究气压治疗仪联合那屈肝素预防剖宫产术后下肢静脉栓塞（DVT）的临床效果。方法：选取2021年1月～2022年8月长沙市妇幼保健院收治的172例剖宫产孕妇,以随机数字表法按1:1比例分为联合组、常规组,各86例。常规组采用那屈肝素预治疗,联合组采用气压治疗仪联合那屈肝素治疗。比较两组DVT发生率;术前、术后5 d凝血功能指标[凝血酶时间（TT）、纤维蛋白原（FIB）、活化部分凝血活酶时间（APTT）、凝血酶原时间（PT）]、血液流变学指标[全血高切黏度、血浆黏度、全血低切黏度];术前、术后1 d、5 d大小腿腿围;术前、术后1 d、3 d、5 d疼痛视觉模拟量表（VAS）评分。结果：联合组DVT发生率3.49%较常规组11.63%低（P＜0.05）;术后5 d联合组PT、APTT、TT较常规组高,FIB较常规组低（P＜0.05）;术后5 d联合组全血高切黏度、血浆黏度、全血低切黏度较常规组低（P＜0.05）;术后1 d、5 d联合组大小腿腿围较常规组低（P＜0.05）;术后1 d、3 d、5 d联合组VAS评分较常规组低（P＜0.05）。结论：气压治疗仪联合那屈肝素能有效改善剖宫产产妇术后凝血功能及血液流变学,缓解下肢肿胀,减轻术后疼痛,减少DVT的发生。     

电针疗法联合全麻诱导对老年下肢关节置换手术患者血流动力学和术后恢复的影响

摘要 目的：评估电针预处理对行下肢关节置换术的老年患者术中血流动力学、术后心血管不良事件、恢复质量的影响。方法：选择择期行下肢关节置换术（膝关节置换或髋关节置换）的老年患者70例,采用随机数字表法分为试验组和对照组。试验组在全麻诱导前30 min于手术准备间予双侧内关、列缺、足三里电针治疗,对照组单纯行全身麻醉。两组全麻诱导后均采用静吸复合麻醉。记录气管插管时（T1）、手术开始后10 min（T2）、拔管后10 min（T3）时的血流动力学参数（HR、MAP、RPP）,术后24 h的心血管不良事件、VAS评分、恢复质量（QoR40）的情况。结果：与对照组相比,试验组T1、T2、T3三个时间点的HR、MAP、RPP均明显降低（P＜0.05）;试验组术后24 h心血管不良事件发生率高于对照组（P＜0.05）,VAS评分以及术后QoR40比较无差异（P>0.05）。结论：麻醉前电针预处理内关、列缺、足三里可以有效的降低患者心率、血压和心肌氧耗量,降低机体对围术期应激的反应,从而降低围术期不良心血管事件的发生率,提高麻醉的安全和质量。     

Redescription of the Chengjiang arthropod Squamacula clypeata Hou and Bergström, from the Lower Cambrian, south-west China

The anatomy of the arthropod Squamacula clypeata Hou and Bergström, 1997 from the Lower Cambrian Chengjiang Lagersta¨tte is redescribed based on four newly excavated specimens. The new material was collected from localities recently discovered in the Kunming area, Yunnan Province, south-west China, and preserves remarkable details of the ventral morphology, revealed by preparation. Squamacula clypeata is dorsoventrally flattened and rounded in outline. The cephalon was covered by a wide, short shield, with a large doublure and a pair of uniramous antennae on the ventral side. The thorax consists of nine somites, each protected by a tergite and carrying at least one pair of biramous limbs. The pygidium is covered with a small rounded tergum. The endopod is segmented, equipped with short spines on the inner margin of the coxa and a claw-like structure distally, and the exopod flap-like, fringed with setae. The limbs in the pygidium are like those in the thorax in shape. Squamacula was most probably a nektobenthic predator. The spinose endopod could walk, grasp and grind. The large flap-like exopod was adapted for swimming and respiration. Its affinities lie with the Arachnomorpha, but the relationships with other known taxa remain ambiguous.     

Lower Devonian Polyplacophora from New South Wales, Australia

Silicified polyplacophorans are common in the Lower Devonian Garra Formation in New South Wales. Four taxa occur within the lower 237 m of the formation at 14 horizons associated with an abundant and diverse fauna. Chelodes calceoloides Etheridge ranges through the section. New taxa are Chelodes cordatus sp. nov., Acutichiton depressolatus sp. nov., and Jugochiton patulus gen. and sp. nov. A single plate of an indeterminate genus occurs in the lower portion of the Camelford Limestone.     

Billingen (Lower Arenig/Lower Ordovician) acritarchs from the East European Platform and their palaeobiogeographic significance

Billingen (Lower Arenig/Lower Ordovician) sediments of the St. Petersburg region, northwest Russia and the Leba area, northern Poland of the East European Craton yield acritarch assemblages, which are largely homogenous though displaying minor compositional differences that probably reflect a gradient from inner to outer shelf environments. Comparison with coeval acritarch microflora from the Yangtze Platform, South China, shows an overall similarity between Baltoscandian and South Chinese phytoplankton. The widespread uniformity in the fossil microphytoplankton may be related to the extensive global 'evae' sea-level transgression, which characterized the Billingen time. This suggests that during the Tremadoc through early Arenig times, acritarch assemblages displayed essentially an undifferentiated cold-water and oceanic character along the whole margin of Perigondwana in the South, as well as on the South Chinese and Baltic platforms, at middle latitudes (Mediterranean oceanic Realm). Despite this overall similarity, however, some typical taxa of the high-latitude Mediterranean Province (Arbusculidium, Coryphidium and Striatotheca) occur in South China, but are absent in Baltica. This discrepancy is explained as caused by differences in climatic and physiographic conditions that prevailed at the two palaeocontinents at this time. The inferred pattern of oceanic circulation during the Lower Ordovician is consistent with the palynological evidence of a prevailing warmer climate in Baltica than in South China, although the two palaeocontinents occupied the same palaeolatitudinal position.     

The early Cambrian helcionelloid mollusc Anabarella Vostokova

One of the oldest known helcionelloid molluscs, Anabarella Vostokova, is redescribed on the basis of type material from the lower Cambrian of north Siberia. Published records of the type species, Anabarella plana Vostokova, show a very wide range in morphology, but studies of variation through ontogeny and in taphonomy confirm assignment to a single variable species. Other described species are reviewed.