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981.
Chen Xiuqin Zhang Zixin Jin Yugan 《Alcheringa: An Australasian Journal of Paleontology》2013,37(3):451-458
The Late Devonian (Famennian) brachiopod Yunnanella is reported from the western Junggar Basin, northern Xinjiang, on the basis of Yunnanella hanburii (Davidson) and Yunnanella sp. 相似文献
982.
Zhong-Qiang Chen Fengqing Yang 《Alcheringa: An Australasian Journal of Paleontology》2013,37(2):163-183
O’Gorman, J.P. &; Gasparini, Z., 2013. Revision of Sulcusuchus erraini (Sauropterygia, Polycotylidae) from the Upper Cretaceous of Patagonia, Argentina. Alcheringa 37, 161–174. ISSN 0311-5518. Sulcusuchus erraini, from the upper Campanian–lower Maastrichtian of Patagonia, Argentina, is the only polycotylid from the Southern Hemisphere for which the skull and mandible are known. The diagnosis of the species and genus is emended based on new observations. Sulcusuchus is characterized by the following autapomorphies: (1) deep and broad rostral and mandibular grooves and (2) a wide notch on the posterior margin of the pterygoids that are combined with a part of the body of the basioccipital, forming a wide plate. Several hypotheses about the identity of the structures that could have been housed in the rostral and mandibular grooves are evaluated. Only two of several hypotheses were not discarded. The first is that the grooves may have accommodated oral glands (supralabial and sublabial), but the biological role of such glands could not be inferred. The second hypothesis is the presence of special structures of an electrosensitive and/or mechanosensitive nature, which might allow the detection of infaunal or semi-infaunal food in soft substrates, as is represented in modern analogues, such as dolphins. José P. O’Gorman [joseogorman@fcnym.unlp.edu.ar] and Zulma Gasparini [zgaspari@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA La Plata, Argentina. Also affiliated with Consejo Nacional de Investigaciones Científicas y Técnicas, Av. Rivadavia 1917 (C1033AAJ), Ciudad Autónoma de Buenos Aires, Argentina and CONICET: Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina Received 5.6.2012; revised 31.7.2012; accepted 4.9.2012. 相似文献
983.
Jian Cai Guobin Bu Jing Zhou Zhiliang Zuo Chun Yang Qingjun Chen 《Journal of Earthquake Engineering》2013,17(1):12-38
This article investigates the ductility reduction factors for RC eccentric frame structures subjected to pulse-like ground motions. The structural models are with the strength eccentricities which are much disadvantageous than the stiffness eccentricities during the inelastic response range. A method to determine the ductility reduction factors of the strength eccentric structures is suggested by modifying those of reference symmetric structures through an eccentricity modification factor. The four factors of strength eccentricity ratio, ductility ratio, story number and velocity pulse of ground motions, are investigated to gain insight into this modification factor. It shows that the ductility reduction factors of the eccentric structures are clearly smaller than those of the symmetric structures. The eccentricity modification factor is mainly affected by the strength eccentricity and the ductility ratio, decreasing with the increment of the eccentricity or the decrement of the ductility ratio in a medium eccentricity range. The earthquake pulse-like effect and the eccentricity have coupling influence on the modification factor, while the effect of story number is not apparent. Based on the results of a comprehensive statistical study a simplified expression is suggested, which can estimate the eccentricity modification factors for both pulse-like and nonpulse-like ground motion cases. 相似文献
984.
Yuanzhi Chen Chern Kun Tam Larkin Nawawi Chouw 《Journal of Earthquake Engineering》2013,17(7):1035-1053
Ground motions recorded in the epicentral region of an earthquake often have a strong vertical component with dominant high frequencies. Damage to bridges in near-source regions due to strong vertical ground motion has been reported. The beneficial effects of footing uplift on structural performance in form of reduction of seismic response of structural members have been confirmed in previous research. The uplift of bridge piers has been utilised in a very limited number of bridge structures, e.g., the South Rangitikei railway bridge in New Zealand. However, the near-fault seismic behaviour of bridges with footing uplift has been even less addressed. In this study shake table investigations were carried out on the response of a single-span bridge model with footing uplift subjected to simultaneous vertical and horizontal excitations. Near-fault ground motions recorded in the Canterbury earthquake sequences of 2010 and 2011 were used. The experimental results show that inclusion of vertical ground motions produce stronger axial force in the pier and larger bending moment in the deck. Concurrent horizontal and vertical excitations may also cause more frequent footing uplift than the solely horizontal excitations. 相似文献
985.
ABSTRACT Contrary to the predictions of the basic spatial equilibrium model, the long‐run distribution of population across rural U.S. counties with high‐valued natural amenities has become relatively more concentrated versus dispersed. We provide an explanation by developing a two‐region model with mobile labor, production externalities and endogenous natural amenities. We find that strong preferences for natural amenities generally foster population dispersion. However, such preferences can also lead to population concentration when ecological degradation is low and man‐made capital is a relatively scarce input into natural amenity production. Investments that enhance natural amenities are found to reduce the divergence between the steady state and optimal outcomes. 相似文献
986.
本文利用二项式分布假设检验方法对黄河流域从裴李岗到大汶口晚期和马厂期男女墓葬中随葬工具的种类和数量的变化进行了统计分析,以揭示劳动按性别分工的问题。这些墓葬的年代范围大致为公元前7000年至2000年之间,正是处于农业生产出现不久后的发展期。根据统计分析,可将随葬工具分为3类:(1)主要由男性使用的工具,(2)主要由女性使用的工具,(3)男女共同使用的工具,其中前两类可视为与性别相关的工具,并计算了每种性别关联型工具在各自遗址或墓地中所占的比例。结果表明,在这一时期中(1)社会劳动中性别分工的增强和细化(性别关联型劳动工具比例的增大和早期一些男女共用型工具晚期转化为主要系男性使用)和(2)男性在社会劳动中优势地位的完全确立(于大汶口晚期在性别关联型工具种类中,主要为男性使用的工具占绝大多数,而主要为女性使用的工具仅留下纺轮一种)。根据这一结果,简单讨论了母系氏族向父系氏族过渡的时间问题。 相似文献
987.
Wu Yuhong published an article on the animals issued to the 6-uz-ga institution and its two cooks, in addition to two articles on the Calendar starting from the Month of Akiti in Puzris-Dagan, in 1996, 2000 and 2002. From 2006, more and more Puzris-Dagan texts have been available to us through BDTNS and CDLI online, and this situation urged us to revise and make a complete archive of the four pairs of cooks (muhaldim) working in the e-uz-ga dining hall, 相似文献
988.
2003年12月贵州人民出版社出版发行的《辛亥革命老人刘莘园遗稿》,其中《联语十则》之第八则有“功在定黔,罪在定黔,乱世为人真不易;朝言革命,暮言革命,先生结局竞如斯”这样一副挽联,根据有关文史资料所述,结合《遗稿》中的作者观点,以及联语中的错字来分析,可知该挽联并非刘莘园作品。 相似文献
989.
990.