Fine structure of bone in dinosaurs, birds and mammals

After observation of detailed structural evidence for the origin of birds from dinosaurs, and in light of evidence that dinosaur bone tissue resembles the histology in mammals, the histology of bone has become one of the focal points in discussions of the physiology of dinosaurs and Mesozoic birds. Most of this microstructural information has focused on features related to the vascular organization and the amount of remodelled bone around vascular canals. However, the finer structures have received less attention, although differences in such structures have been observed among modern vertebrates. Here we present evidence that canaliculi--the submicrometre-sized channels that interconnect bone cells and vascular canals--and the collagen fibre bundles in bone are differently organized among certain dinosaur lineages. Ornithomimid dinosaurs are more like birds than mammals in these features. In canalicular structure, and to some extent in fibre bundle arrangement, ornithischian dinosaurs are more like mammals. These differences in both canalicular and lamellar structure are probably linked to differences in the process and rate of bone formation.     

Adaptive radiation of multituberculate mammals before the extinction of dinosaurs

The Cretaceous-Paleogene mass extinction approximately 66 million years ago is conventionally thought to have been a turning point in mammalian evolution. Prior to that event and for the first two-thirds of their evolutionary history, mammals were mostly confined to roles as generalized, small-bodied, nocturnal insectivores, presumably under selection pressures from dinosaurs. Release from these pressures, by extinction of non-avian dinosaurs at the Cretaceous-Paleogene boundary, triggered ecological diversification of mammals. Although recent individual fossil discoveries have shown that some mammalian lineages diversified ecologically during the Mesozoic era, comprehensive ecological analyses of mammalian groups crossing the Cretaceous-Paleogene boundary are lacking. Such analyses are needed because diversification analyses of living taxa allow only indirect inferences of past ecosystems. Here we show that in arguably the most evolutionarily successful clade of Mesozoic mammals, the Multituberculata, an adaptive radiation began at least 20 million years before the extinction of non-avian dinosaurs and continued across the Cretaceous-Paleogene boundary. Disparity in dental complexity, which relates to the range of diets, rose sharply in step with generic richness and disparity in body size. Moreover, maximum dental complexity and body size demonstrate an adaptive shift towards increased herbivory. This dietary expansion tracked the ecological rise of angiosperms and suggests that the resources that were available to multituberculates were relatively unaffected by the Cretaceous-Paleogene mass extinction. Taken together, our results indicate that mammals were able to take advantage of new ecological opportunities in the Mesozoic and that at least some of these opportunities persisted through the Cretaceous-Paleogene mass extinction. Similar broad-scale ecomorphological inventories of other radiations may help to constrain the possible causes of mass extinctions.     

New evidence on deinonychosaurian dinosaurs from the Late Cretaceous of Patagonia

Most of what is known about the evolution of deinonychosaurs (that is, the group of theropods most closely related to birds) is based on discoveries from North America and Asia. Except for Unenlagia comahuensis and some fragmentary remains from northern Africa, no other evidence was available on deinonychosaurian diversity in Gondwana. Here we report a new, Late Cretaceous member of the clade, Neuquenraptor argentinus gen. et sp. nov., representing uncontroversial evidence of a deinonychosaurian theropod in the Southern Hemisphere. The new discovery demonstrates that Cretaceous theropod faunas from the southern continents shared greater similarity with those of the northern landmasses than previously thought. Available evidence suggests that deinonychosaurians were probably distributed worldwide at least by the beginning of the Cretaceous period. The phylogenetic position of the new deinonychosaur, as well as other Patagonian coelurosaurian theropods, is compatible with a vicariance model of diversification for some groups of Gondwanan and Laurasian dinosaurs.     

关于华南推覆构造的商榷

根据前寒武纪花岗岩以及青白口纪火山岩与上(板)溪群之间的侵入接触关系,确定上溪群形成年龄为中元古代。皖南与赣东北蛇绿岩套的Sm-Nd定年结果为约1.0Ga。因此华南地块于中生代推覆到扬子地块上的模式不符合基本的地质事实。现有资料支持华夏和扬子两地块在晚元古代碰撞拼合的解释。     

哺乳动物卵子发生过程中细胞凋亡的研究进展

细胞凋亡是发育过程中的基本生命现象,是多细胞生物体一种重要的自我稳定机制．除各种体细胞凋亡外,生殖细胞在其发生过程中也有细胞凋亡现象产生．对许多脊椎动物和无脊椎动物的研究发现,有大量生殖细胞在其发育的不同阶段丢失．对近10年来哺乳动物卵子发生过程中细胞凋亡的研究进行了综述,主要描述了哺乳动物卵子发生过程中的细胞凋亡及其调控以及凋亡的意义．     

Climate-mediated energetic constraints on the distribution of hibernating mammals

To predict the consequences of human-induced global climate change, we need to understand how climate is linked to biogeography. Energetic constraints are commonly invoked to explain animal distributions, and physiological parameters are known to vary along distributional gradients. But the causal nature of the links between climate and animal biogeography remain largely obscure. Here we develop a bioenergetic model that predicts the feasibility of mammalian hibernation under different climatic conditions. As an example, we use the well-quantified hibernation energetics of the little brown bat (Myotis lucifugus) to parameterize the model. Our model predicts pronounced effects of ambient temperature on total winter energy requirements, and a relatively narrow combination of hibernaculum temperatures and winter lengths permitting successful hibernation. Microhabitat and northern distribution limits of M. lucifugus are consistent with model predictions, suggesting that the thermal dependence of hibernation energetics constrains the biogeography of this species. Integrating projections of climate change into our model predicts a pronounced northward range expansion of hibernating bats within the next 80 years. Bioenergetics can provide the simple link between climate and biogeography needed to predict the consequences of climate change.     

黄山地区中生代碎屑岩区域地质灾害成因的探究

随着皖南山区公路和城市的迅速发展,地质灾害愈来愈频繁.文章选择黄山地区中生代碎屑岩分布区地质灾害作为研究对象,从区域地层岩性的研究人手以及对其他地质灾害控制因素的分析,得出了人类的工程活动是黄山地区中生代碎屑岩区域地质灾害发生的主要因素.     

An oviraptorid preserved atop an embryo-bearing egg clutch sheds light on the reproductive biology of non-avialan theropod dinosaurs

Recent studies demonstrate that many avialan features evolved incrementally prior to the origin of the group,but the presence of some of these features,such as ...     

新疆准噶尔盆地西北缘中生代盆地边界探讨

目的 确定准噶尔盆地中生代西北缘盆地边界.方法 对准噶尔盆地西北缘扎伊尔山-哈拉阿拉特山两侧沉积盆地的沉积特征、沉积充填过程及古水流恢复等方面进行研究.结果 早中生代,准噶尔盆地西北缘以扎伊尔山-哈拉阿拉特山为界,其北侧的和什托洛盖盆地在三叠纪-中侏罗世是独立于准噶尔盆地而发育在古生代褶皱基地之上的断陷盆地.白垩纪以来,和什托洛盖盆地与准噶尔盆地连为一体,成为一个统一发育的拗陷盆地,盆地边界位于和什托洛盖盆地北侧谢米斯台山一带.结论 准噶尔盆地西北缘中生代以来,在扎伊尔山-哈拉阿拉特山两侧盆地具有不同的沉积特征、沉积充填过程和古水流样式,和什托洛盖盆地具有独立的沉积体系和古水流样式.     

吊罗山保护区哺乳动物物种多样性初步研究

根据实地调查和资料记载,海南吊罗山共有哺乳动物8目2l科46种,分别占海南省哺乳动物(水生兽类除外)9目、24科、76种的88．89％、87．50％和60．53％,其中华南麝鼯、犬蝠、小菊头蝠、中华鼠耳蝠、大长翼蝠、灰伏翼、屋顶鼠和社鼠等8种为吊罗山保护区新记录;黑长臂猿和云豹2种为国家Ⅰ级重点保护动物,猕猴、黑熊等9种为国家Ⅱ级重点保护动物,分别占海南省国家Ⅰ、Ⅱ级重点保护动物(水生兽类除外)的66．67％和90．0％;还有14种列入国家“三有”保护动物,17种列入中国动物红皮书,6种列入IUCN红皮书,有4、5、4种分别列入CITES公约附录Ⅰ、Ⅱ、Ⅲ;海南毛猬、大鼯鼠2种为海南特产种(占海南特产种的66．67％)．黑长臂猿(又称海南长臂猿)、小缺齿鼹(又称华南缺齿鼹)、中菊头蝠(海南菊头蝠)等12种为海南特产亚种．     

宁夏哺乳动物地理分布的聚类分析

用组平均法对宁夏哺乳动物地理分布区进行聚类,６ 个动物地理州在距离系数为０．３８７０ 时聚为４ 个类群,在距离系数为０．５１４９ 水平聚合为２ 个类群组．聚类结果与中国动物地理区划中宁夏跨２ 个动物地理区及宁南、宁中北分属华北区黄土高原亚区和蒙新区东部草原亚区的划分相吻合,而与宁夏西北边缘的贺兰山地和腾格里沙漠东南缘同属蒙新区西部荒漠亚区的划分不吻合．文章对聚类结果作了分析,比较了应用不同匹配系数公式对动物地理分布聚类结果的影响．     

风化店中生界火山岩的归属问题及岩石类型

认为风化店中生界火山岩层呈层状分布，其间夹火山碎屑岩和沉积碉夹层；岩石的气孔及流纹构造发育，矿物学特征显示出喷出岩中矿物所具有的特性；岩石的氧化度较高，Ｆｅ２Ｏ３／（Ｆｅ２Ｏ３＋ＦｅＯ）平均为５３．５０％，ＳｉＯ２的含量平均为６８．４６％。根据岩体地质特征．岩石学及岩石化学等证据，认为绝大部分岩石属于钙碱性酸火山喷出岩，只有少部分为偏碱性中性或偏碱性中酸性火山喷出岩。岩石类型主要为英安流纹岩、流纹     

大采深大型矿井井下降温设计研究

本文以朱集西矿这种典型的大采深、地温高、机电设备散热量大,热害程度严重的大型矿井为研究对象,提出地面两级制冷,大温差输送冷量,采用高低压换热器解决高静压的方法,解决了这类高温矿井排热困难,大采深矿井静水压大的难题,提出了采用国产设备解决大型高温矿井井下降温的设计方法。     

双馈电机运行速度对稳态性能的影响

研究双馈电机运行速度对双馈电机稳态性能的影响．首先对比了双馈电机运行于超同步转速及次同步转速时的稳态波形，然后对谐波及稳态参数的变化进行了分析．研究表明双馈电机稳态运行速度对其稳态运行性能有较大影响．     

东秦岭—大别地区中生代岩石圈拆沉的岩石学证据评述

岩石圈拆沉是碰撞造山带物质成分调整和构造演化的重要方式之一。构造地质研究、地球物理探测和地球化学分析等都已揭示东秦岭-大别造山带曾在中生代发生岩石圈拆沉,但有关中生代变质作用和岩浆活动与岩石圈拆沉的内在联系研究却较为薄弱。通过全面评述该区变质岩研究成果,作者认为：超高压变质岩的形成和剥露经历了240～200Ma的板片冷俯冲冷折返和196～163Ma的岩石圈拆沉热折返;热折返伴随了广泛而强烈的区域变质作用和中酸性岩浆活动,指示板片断离拆沉的发生;超高压变质岩p-T-t轨迹由两部分组成,即反映板片冷俯冲冷折返过程的发夹状曲线和指示板片断离拆沉热折返过程的新月形曲线。通过对花岗岩类同位素年龄统计和前人研究成果的评述,初步确定在200～100Ma之间发育大量花岗岩类,并集中在150～100Ma为主(即侏罗纪—白垩纪之交),高峰时间为130Ma左右;花岗岩类大量发育指示了岩石圈拆沉的存在,且滞后于根据变质岩研究所揭示的拆沉时间。羌塘地体、拉萨地体和西太平洋古陆在侏罗纪与欧亚大陆拼贴碰撞的远距离效应使东秦岭—大别造山带长期处于挤压环境,伸展作用被抑制;白垩纪的碰撞晚期伸展和西太平洋沟弧盆体系的远距离效应使东秦岭—大别地区的外部挤压消失,导致造山带岩石圈迅速强烈拆沉伸展和减压增温熔融,从而形成大规模早白垩世花岗岩类和中酸性火山岩。总之,东秦岭—大别地区岩石圈拆沉所导致的岩浆活动主要发生在J₃—K₁的挤压伸展转变期。     

哈密拗陷中生界砂岩孔隙结构特征初探

通过砂岩铸体薄片、扫描电镜观察、毛细管压力数据及物性参数等资料，对哈密拗陷中生界砂岩储层的孔隙结构特征进行了初步研究。划分出了粒间孔隙、溶蚀孔隙、填隙物内孔隙及裂缝等４种主要孔隙类型，对砂岩孔隙结构特征进行了评价。分析了影响本区中生界砂岩储层孔隙结构的地质因素，为下一步的油气勘探提供了必要的地质基础和理论依据。     

彰武地区中生代张强凹陷地热史研究

对张强凹陷粘土矿物Ｘ射线衍射谱线特征及有机质干酪根类型的定性分析和镜质体反射率（Ｒ０）与温度之间关系的定量模拟计算，恢复了凹陷的地热史；通过古热流的计算，恢复了凹陷的热沉降史，从定量的角度进一步证实了凹陷古热流在时间上表现为由低→高→低的变化规律，从而证实了凹陷属于裂谷盆地．通过研究，指出对凹陷进行进一步勘探开发有利的生油层位．     

核电站大型吊具应力测试分析

对吊具结构进行了分析和计算,介绍了载荷试验过程和应力测试,得出了吊具静态应力和动态应力的测试结果。