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1.
Here we report an unequivocal arboreal coelurosaur, Epidendrosaurus ningchengensis gen. et sp. nov. This juvenile coelurosaur's third manual digit is extremely elongated, distinctively different from that of other known dinosaurs and birds. It represents certainly a type of adaptation previously unreported from the Mesozoic although the exact function of the third manual digit is unclear. The relatively long forelimb, penultimate phalanx of manual digit II, and pedal penultimate phalanges, are interpreted as evidence for the arboreal habit of Epidendrosaurus. Because Epidendrosaurus is more similar to advanced birds in some arboreal features than to Archaeopteryx, we suggest that the initial appearance of tree-adaptation in theropods was probably not directly related to flight but to other functions, such as seeking food or escaping from predators. Electronic Supplementary Material is available if you access this article at http://dx.doi.org/10.1007/s00114-002-0353-8. On that page (frame on the left side), a link takes you directly to the supplementary material. 相似文献
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A juvenile lizard specimen with well-preserved skin impressions from the Upper Jurassic/Lower Cretaceous of Daohugou, Inner Mongolia, China 总被引:1,自引:0,他引:1
Lizards are now relatively well known from the Yixian Formation of northeastern China. In this study, we describe a juvenile
lizard from a fossil horizon at Daohugou, Inner Mongolia. These beds predate the Yixian Formation, and are probably Late Jurassic
or earliest Cretaceous in age. The new specimen thus documents the first lizard material from the Daohugou locality and is
the earliest lizard skeleton from China. Comparisons with developmental stages of modern lizards suggest the Daohugou lizard
is a hatchling. Although tiny, the specimen is notable in preserving exquisite skin impressions showing the variation in scalation
across the body, the shape and position of the cloacal outlet, and details of the manus and pes. These are the earliest recorded
lepidosaurian skin traces. In its general proportions and the possession of paired frontals, the small Daohugou lizard resembles
both the Yixian taxon Yabeinosaurus tenuis and the questionable Jeholacerta formosa, but it differs from the latter in scalation and, based on other characters, may be distinct from both. 相似文献
3.
西方媒体所描述的中国,远非我们这些居住在中国的外国人所目睹的真实的中国,在分享着这个不可思议的、充满活力的国家所呈现的喜悦和进步的同时,我们不得不被她的魅力深深吸引。 相似文献
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Wei Wang Yuxiang Luo Zhou Deng 《Frontiers of Environmental Science & Engineering in China》2009,3(1):20-31
Landfill gas (LFG) utilization which means a synergy between environmental protection and bioenergy recovery was investigated
in this study. Pressure swing adsorption technology was used in LFG purification, and laboratory experiment, pilot-scale test,
and on-site demonstration were carried out in Shenzhen, China. In the laboratory experiment, A-type carbon molecular sieve
was selected as the adsorbent by comparison of several other adsorbents. The optimal adsorption pressure and adsorption time
were 0.25 MPa and 2 min, respectively, under which the product generation rate was 4.5 m3/h and the methane concentration was above 90%. The process and optimization of the pilot-scale test were also reported in
the paper. The product gas was of high quality compared with the National Standard of Compressed Natural Gas as Vehicle Fuel
(GB18047-2000), when the air concentration in feed gas was under 10.96%. The demonstration project was composed of a collection
system, production system, and utilization system. The drive performance, environmental protection performance, and economic
feasibility of the product gas — as alternative fuel in passenger car, truck, and bulldozer—were tested, showing the feasibility
technology for LFG utilization. 相似文献
6.
中国农药废水处理技术现状 总被引:9,自引:0,他引:9
现代废水处理技术按原理可分为物理处理法、化学处理法、生物化学处理法.文章对上述方法在中国农药废水处理中的应用进行了简要的介绍,并对近几年来的农药废水处理新技术的发展进行了探讨. 相似文献
7.
The unusual presence of long pennaceous feathers on the feet of basal dromaeosaurid dinosaurs has recently been presented as strong evidence in support of the arboreal–gliding hypothesis for the origin of bird flight, but it could be a unique feature of dromaeosaurids and thus irrelevant to the theropod–bird transition. Here, we report a new eumaniraptoran theropod from China, with avian affinities, which also has long pennaceous feathers on its feet. This suggests that such morphology might represent a primitive adaptation close to the theropod–bird transition. The long metatarsus feathers are likely primitive for Eumaniraptora and might have played an important role in the origin of avian flight.Electronic Supplementary Material Supplementary material is available for this article at 相似文献
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从台湾岛基本地质特征出发,通过与大陆东南沿海及邻近地区之间的地质对比,提出关于台湾岛成因的新假说,即台湾岛是在晚中生代随着东南大陆的离散而逐渐分离出去的一个陆块,并经历逆时针旋转,于中新世以后在福建沿海与大陆碰撞拼贴. 相似文献
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Mitigation and Adaptation Strategies for Global Change - Carbon dioxide (CO2) emissions from China are of global concern. As energy-, resource-intensive and greenhouse gas (GHG) pollution... 相似文献
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在中国范围内民航运输飞机及所配装的发动机的型号和有关设计工作参数等的基础上,借鉴目前国际上通行的方法,对飞机与发动机的运行过程进行简化和建模,并根据国际民航组织(ICAO)和美国航空航天管理局(NASA)等公布的航空发动机在海平面静态的排放数据,采用国际通用的油流量算法,对1997年中国上空民航飞机的氮氧化物(NOx)排放量进行了估算,并结合国内外有关数据进行了分析和比较.结果表明,中国各城市上空的大气污染程度有很大不同,大部分城市上空的大气目前已处于轻度污染,个别城市上空的大气污染程度已相当于欧美等发达国家1992年初的排放水平,其严重性亟待引起政府部门和有关专家的注意. 相似文献
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Liquan Zhang Zhanguo Gao Richard Armitage Martin Kent 《Frontiers of Environmental Science & Engineering in China》2008,2(2):187-197
The spectral reflectance of recently formed salt marshes at the mouth of the Yangtze River, which are undergoing invasion
by Spartina alterniflora, were assessed to determine the potential utility of remotely sensed data in assessing future invasion and changes in species
composition. Following a review of published research on remote sensing of salt marshes, 53 locations along three transects
were sampled for paired data on plant species composition and spectral reflectance using a FieldSpec™ Pro JR Field Portable
Spectroradiometer. Spectral data were processed concerning reflectance, and the averaged reflectance values for each sample
were reanalysed to correspond to a 12-waveband bandset of the Compact Airborne Spectral Imager. The spectral data were summarised
using principal components analysis (PCA) and the relationships between the vegetation composition, and the PCA axes of spectral
data were examined. The first PCA axis of the reflectance data showed a strong correlation with variability in near infrared
reflectance and ‘brightness’, while the second axis was correlated with visible reflectance and ‘greenness’. Total vegetation
cover, vegetation height, and mudflat cover were all significantly related to the first axis. The implications of this in
terms of the ability of remote sensing to distinguish the various salt marsh species and in particular the invasive species
S. alterniflora were discussed. Major differences in species with various physiognomies could be recognised but problems occurred in separating
early colonising S. alterniflora from other species at that stage. Further work using multi-seasonal hyperspectral data might assist in solving these problems. 相似文献
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Phosphatic (possibly secondarily phosphatised) remains of antipatharian coralla, previously unknown in the fossil record, occur abundantly in the early Ordovician Fenxiang Formation in the Hubei Province, southern China. Probably two species (and genera) are represented, which differ in spinosity of branches. The more spinose one, Sinopathes reptans, has its lateral spines bearing regular, longitudinally arranged costellae. The early Floian geological age of this finding, about 470?Ma, supports predictions on the timing of anthozoan phylogeny derived from the molecular phylogenetic evidence. Black corals (Antipatharia) are basal to the scleractinians in the Hexacorallia clade, being more derived than sea anemones and the Zoantharia. Based on calibration of the molecular clock with Mesozoic data, the first split of lineages within the scleractinian hexacorals was proposed to take place approximately 425 million years ago. This implies that the origin of Antipatharia should precede this date. They have not been known in the fossil record because of unmineralised skeleton composed primarily of laminar chitin complexed with a protein. Unlike all recent species, the encrusting basal part of the colony dominated in the Ordovician ones and only occasionally erect branches developed, rather chaotically ramified. This presumably plesiomorphic trait seems consistent with ancient geological age and suggests that some problematic fossils from the Late Cambrian may be their, even less-derived, relatives. 相似文献
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东海的环境面临着长江流域及沿海地区人类活动和污染增长的巨大威胁.对自然资源的不合理利用及短期经济目标导致了环境在相当短的时间内出现了严重退化,现在已达到威胁沿海人民生命和健康的程度.主要污染物是无机氮、磷酸盐、石油类、有机物及重金属.营养物导致了沿海水域和河口的富营养化,常常引发赤潮.长江流域的环境污染直接影响了东海的海洋环境状况.稳定的河流来水在河口与海洋咸水混合,河流带来的泥沙平衡了三角洲及相邻地区的海洋侵蚀,这样,生态系统稳定性才能得到维持.长江流域的大规模调水及大坝的修建将改变这种基础.东海面临的挑战是扭转正在发生的负面过程,保持生态系统平衡.主要任务是把社会经济与环境决策结合起来,以促进可持续发展.需要更好地了解造成这些环境压力的社会驱动力,以克服这些障碍.国际合作也许能为促进进步作出重要贡献,尤其是,国际合作是取得良好进展和获得资金、技术、科学及人力资源的途径. 相似文献
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Ulysse Lefèvre Andrea Cau Aude Cincotta Dongyu Hu Anusuya Chinsamy François Escuillié Pascal Godefroit 《Die Naturwissenschaften》2017,104(9-10):74
Genuine fossils with exquisitely preserved plumage from the Late Jurassic and Early Cretaceous of northeastern China have recently revealed that bird-like theropod dinosaurs had long pennaceous feathers along their hindlimbs and may have used their four wings to glide or fly. Thus, it has been postulated that early bird flight might initially have involved four wings (Xu et al. Nature 421:335–340, 2003; Hu et al. Nature 461:640–643, 2009; Han et al. Nat Commun 5:4382, 2014). Here, we describe Serikornis sungei gen. et sp. nov., a new feathered theropod from the Tiaojishan Fm (Late Jurassic) of Liaoning Province, China. Its skeletal morphology suggests a ground-dwelling ecology with no flying adaptations. Our phylogenetic analysis places Serikornis, together with other Late Jurassic paravians from China, as a basal paravians, outside the Eumaniraptora clade. The tail of Serikornis is covered proximally by filaments and distally by slender rectrices. Thin symmetrical remiges lacking barbules are attached along its forelimbs and elongate hindlimb feathers extend up to its toes, suggesting that hindlimb remiges evolved in ground-dwelling maniraptorans before being co-opted to an arboreal lifestyle or flight. 相似文献
18.
Although viviparity is most often associated with mammals, roughly one fifth of extant squamate reptiles give birth to live
young. Phylogenetic analyses indicate that the trait evolved more than 100 times within Squamata, a frequency greater than
that of all other vertebrate clades combined. However, there is debate as to the antiquity of the trait and, until now, the
only direct fossil evidence of squamate viviparity was in Late Cretaceous mosasauroids, specialised marine lizards without
modern equivalents. Here, we document viviparity in a specimen of a more generalised lizard, Yabeinosaurus, from the Early Cretaceous of China. The gravid female contains more than 15 young at a level of skeletal development corresponding
to that of late embryos of living viviparous lizards. This specimen documents the first occurrence of viviparity in a fossil
reptile that was largely terrestrial in life, and extends the temporal distribution of the trait in squamates by at least
30 Ma. As Yabeinosaurus occupies a relatively basal position within crown-group squamates, it suggests that the anatomical and physiological preconditions
for viviparity arose early within Squamata. 相似文献
19.
中国海水养殖污染负荷估算 总被引:1,自引:0,他引:1
近年来,在国民对水产品消费需求的驱动下,中国海水养殖规模不断增加,加剧沿岸水域富营养化程度。本文基于水产养殖排污系数调查手册和渔业统计年鉴,估算我国海水养殖过程中污染物排放总量,建立养殖总产量与污染负荷总量之间的回归关系,使用蒙特卡罗方法量化参数的不确定性并进行情景模拟。结果表明:2012年,中国海水养殖过程向相关海域排放TN、TP、COD、Cu和Zn分别为17414 t、3146 t、55503 t、53 t以及242 t;各沿海省份污染负荷总量与养殖总产量存在线性关系,其总氮、总磷和COD的相关系数r分别为0.974、0.975和0.996;敏感性分析表明,养殖类型是影响污染物排放总量的最重要因素。优化养殖类型和调整养殖方法是减少我国海水养殖污染负荷的重要途径。 相似文献
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基于中国2013~2015年27个省(区、市)平板玻璃企业的逐生产线基础信息、活动水平及污染物控制技术等数据,建立了平板玻璃主要大气污染物SO2、NOx排放量计算方法和排放清单,使用蒙特卡洛法进行了不确定性分析.统计了平板玻璃产量、燃料使用量、燃料结构以及污染物控制技术,分析了排放特征与空间差异.结果表明:中国平板玻璃行业以天然气/煤气为主要燃料,平均单位产品能源消耗量为13.2kg标煤/重量箱,山西、内蒙古等省份较高;37%和42%的生产线分别安装了脱硫、脱硝设施,技术以烟气循环流化床、双碱法、SCR为主;SO2排放量先升后降,2014年达到16.84万t,2015年下降至13.67万t,湖北、浙江、河北、广东排放量较大;NOx排放量持续下降,从2013年的37.47万t下降至2015年的28.38万t,河北、湖北、山东、广东排放量较大;SO2排放强度西南部地区高于其他地区,且有上升趋势,其他地区SO2排放强度整体下降;NOx排放强度中西部地区较高.应加强高能耗、高排放以及高强度地区的污染控制力度. 相似文献