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1.
裴文中教授在60年前发现的北京猿人第一个头盖骨埋藏的确切年代至今没有获得。本文通过对北京猿人共生的古脊椎动物牙化石进行电子自旋共振(ESR)测年,分别获得了第11层北京猿人第一个头盖骨埋藏的年代为578千年,第8—9层和第3—4层北京猿人埋藏的年代分别为418千年和282千年。依据ESR、U系,TL,FT和古地磁等测年结果,本文推荐了北京猿人洞的洞穴堆积层(周口店组Q_2)年代表供读者参考。  相似文献   

2.
本文综合评述了对周口店第一地点的测年结果。探讨了1)基于骨化石铀系、裂变径迹、古地磁和牙化石ESR测年的老年代框架与2)基于钙板铀系和铝铍埋藏测年的新年代框架之间的差异。着重分析了铝铍埋藏年龄测量方法因假设前提不完全满足而可能引起测年结果偏老的系统误差。文中还对周口店遗址进一步的年代学研究提出了建议。  相似文献   

3.
The Xujiayao-Houjiayao site in Nihewan Basin is among the most important Paleolithic sites in China for having provided a rich collection of hominin and mammalian fossils and lithic artifacts. Based on biostratigraphical correlation and exploratory results from a variety of dating methods, the site has been widely accepted as early Upper Pleistocene in time. However, more recent paleomagnetic analyses assigned a much older age of ∼500 ka (thousand years). This paper reports the application of 26Al/10Be burial dating as an independent check. Two quartz samples from a lower cultural horizon give a weighted mean age of 0.24 ± 0.05 Ma (million years, 1σ). The site is thus younger than 340 ka at 95% confidence, which is at variance with the previous paleomagnetic results. On the other hand, our result suggests an age of older than 140 ka for the site’s lower cultural deposits, which is consistent with recent post-infrared infrared stimulated luminescence (pIR-IRSL) dating at 160–220 ka.  相似文献   

4.
泥河湾盆地几处旧石器时代文化遗址光释光测年   总被引:1,自引:0,他引:1  
中国泥河湾盆地几处旧石器时代考古遗址经过光释光年代测试,分别得出IRSL和BLSL年龄。油房遗址文化层上下部层位分别为1.3—1.4万年和1.5—1.7万年,虎头梁遗址上部层位为0.9±0.13万年,许家窑遗址文化层约为6.9±0.8万年。  相似文献   

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6.
1 IntroductionTheLuonanBasinisasmallintermountainbasin .Itisabout 1 50kmnorthwestofthecityofXi an ,China .Thelengthofthebasinisabout 50kmfromwesttoeastandthewidthis 1 0— 2 0kmfromnorthtosouth .Theflooriswideatitswesternendandnarrowatitseasternend .Slopeisthemostimportantaspectofland surfaceconfiguration .GeologicallythebasinissandwichedbetweentheHuashanMountainsandtheMonglingMountainsintheeasternpartoftheQinlingMountains .ItwasformedduringtheMesozoicEraasaresultoffaultingandsedimentation .Thealtituderangesf...  相似文献   

7.
我国早、中更新世古人类和旧石器遗址蕴含着丰富的早期人类活动和生存环境的背景信息,建立精确的遗址年代序列是分析古人类活动的基础。近二十年来,旧石器时代考古和测年研究为建立我国早期人类活动的年代框架提供了丰富的材料。本文分析了目前我国已发表的95个有独立测年数据的早、中更新世遗址,将其纳入黄土-古土壤年代框架,初步建立自200多万年至末次间冰期的古人类活动年代序列,根据它们的时空分布,进一步阐释了古人类在不同区域活动强度演变的时空特征。总体来看,这些遗址在泥河湾-周口店、秦岭山地、长江下游及长江流域以南(南方)四大区域呈现出聚集分布的特征;区域古人类活动强度主要表现在从早更新世的泥河湾-周口店、中更新世的秦岭山地、到中更新世晚期的长江中下游和南方区域的时空序列上。此外,仍有较多已发掘遗址缺少年代研究或存在测年问题,今后需要加强遗址的精确测年研究。  相似文献   

8.
目的:分析ART患者早期流产组织染色体异常及其相关影响因素。方法:回顾性分析2013-2017年ART患者行早期流产组织染色体检查的409例样本,分析胚胎染色体非整倍性发生及其与女方年龄、不孕年限、不孕因素、促排卵指标之间的关系。结果:ART流产患者中,流产组织染色体非整倍性发生率为57.46%,发生频次以16三体占比最高(23.95%),其次是22三体(13.45%)及Turner(9.24%)。流产组织染色体非整倍性患者平均年龄高于染色体整倍性患者(P0.001)。16三体组患者年龄低于22三体(P0.01)及Turner组(P0.05)。16三体组患者平均Gn使用量低于22三体组(P0.05)。16三体组患者移植15天血HCG值低于22三体(P0.05)及Turner组(P0.01)。结论:ART患者流产组织染色体非整倍性与女方年龄正相关,但16三体及Turner的发生与女方年龄相关性不大,且16三体更容易引发早期流产。  相似文献   

9.
Abstract: Calcitonin gene-related peptide (CGRP), a 37-amino-acid peptide, is a member of a small family of peptides including amylin or islet amyloid polypeptide and salmon calcitonin. These related peptides have been shown to display similar effects on in vitro and in vivo carbohydrate metabolism. The present study was initiated to identify and characterize the binding sites for these peptides in lung and nucleus accumbens membranes prepared from pig and guinea pig. Both tissues in either species displayed high-affinity (2-[125I]iodohistidyl10)humanCGRPα ([125I]hCGRPα) binding (IC50 = 0.4–7.7 nM), which was displaced by hCGRP8–37α with equally high affinity (IC50 = 0.4–7.3 nM). High-affinity binding for [125I]Bolton-Hunter human amylin ([125I]BH-h-amylin) was also observed in these tissues (IC50 = 0.2–6.0 nM). In membranes from the nucleus accumbens of both species, salmon calcitonin competed for amylin binding sites with high affinity (IC50 = 0.1 nM) but was poor in competing for amylin binding in lung membranes. Rat amylin8–37 competed for [125I]hCGRPα binding with higher affinity (IC50 = 5.4 nM) compared with [125I]BH-h-amylin binding (IC50 = 200 nM) in porcine nucleus accumbens, whereas in guinea pig nucleus accumbens, the IC50 values for rat amylin8–37 were 117 and 12 nM against [125I]hCGRPα and [125I]BH-h-amylin, respectively. Also, functional studies evaluating the activation of adenylate cyclase and generation of cyclic AMP in response to these agonists indicated that hCGRPα (EC50 = 0.3 nM), h-amylin (EC50 = 150 nM), and salmon calcitonin (EC50 = 1,000 nM) activated adenylate cyclase, resulting in increased cyclic AMP production in porcine lung membranes that was antagonized by hCGRP8–37α. The affinity of hCGRP8–37α was similar for all three peptides. The cyclic AMP responses to amylin and salmon calcitonin were significantly (p < 0.05) lower than that of hCGRPα and not additive, suggesting that they are acting as partial agonists at the same CGRP1-type receptor in porcine lung membranes. Similar observations were made for guinea pig lung membranes. However, human amylin and salmon calcitonin were weaker than hCGRPα in activating lung adenylate cyclase. None of these peptides activated adenylate cyclase in membranes prepared from the nucleus accumbens of both species. The data from these studies demonstrate both species and tissue differences in the existence of distinct CGRP and amylin binding sites and present a potential opportunity to study further CGRP and amylin receptor subtypes.  相似文献   

10.
目的:探讨孕早期妇女血清25-羟维生素D[25(OH)D]水平及与甲状腺功能的相关性。方法:选取2015年12月至2016年12月期间来我院进行常规产前检查的孕早期(≤12周)妇女90例为观察组,根据妊娠时间将观察组分为A组(4-6周)、B组(7-9周)和C组(10-12周),另选取同期在我院进行健康体检的妇女30例为对照组。采用电化学发光免疫分析法测定所有研究对象血清中的25(OH)D、促甲状腺激素(TSH)、游离甲状腺素(FT4)、游离三碘甲状腺原氨酸(FT3)水平,并分析观察组妇女血清25(OH)D水平与TSH、FT4、FT3之间的相关性。结果:A组、B组、C组出现维生素D缺乏的比例高于对照组,维生素D充足的比例低于对照组,C组出现维生素D不足的比例高于对照组,差异均有统计学意义(P0.05)。A组、B组、C组维生素D缺乏、维生素D不足、维生素D充足的比例之间差异无统计学意义(P0.05)。A组、B组、C组出现甲状腺功能异常的比例比较差异无统计学意义(P0.05)。三种甲状腺功能减退的患病率由低到高分别为临床甲减、亚临床甲减、低T4血症,且A组、B组、C组临床甲减、亚临床甲减及低T4血症组间整体比较差异无统计学意义(P0.05)。不同血清25(OH)D水平的观察组孕妇血清中TSH、FT4、FT3水平之间的差异无统计学意义(P0.05)。直线回归分析显示,观察组血清中25(OH)D水平与TSH、FT4无明显相关性(P0.05),与FT3呈正相关关系(P0.05),多元线性回归模型分析显示血清中25(OH)D水平与TSH、FT4、FT3均无相关性(P0.05)。结论:孕早期妇女普遍存在维生素D缺乏的现象,血清25(OH)D水平及与甲状腺功能无明显相关性,但仍应注意加强维生素D的补充。  相似文献   

11.
The detailed structure of the lophophore is a key diagnostic character in the definition of higher brachiopod taxa. The problematic Heliomedusa orienta Sun and Hou, from the Lower Cambrian Chengjiang Lagerstätte of Yunnan, southwestern China, has a well-preserved lophophore, which is unlike that of any known extant or extinct brachiopods. Based on a comparative study of lophophore disposition in H. orienta and the extant discinid Pelagodiscus atlanticus, the in- and excurrent pattern and shell orientation of H. orienta are described and discussed. Reconstructions of lophophore shape and function are based on numerous specimens and comparison with P. atlanticus. The lophophore is composed of a pair of lophophoral arms that freely arch posteriorly rather than coiling anteriorly as commonly seen in fossil and recent lingulids. The lophophore is attached to the dorsal lobe of the mantle; it has neither calcareous nor chitinous supporting structures, and is disposed symmetrically on either side of the valve midline. The mouth can be inferred to be located at the base of the two brachial tubes, slightly posterior to the anterodorsal projection of the body wall. The lophophoral arms bear laterofrontal tentacles with a double row of cilia along their lateral edge, as in extant lingulid brachiopods. The main brachial axes are also ciliated, which presumably facilitated transport of mucous-bound nutrient particles to the mouth. The unique organization of the lophophore in Heliomedusa is not like any known fossil and living brachiopods. This clearly demonstrates that H. orienta is not a member of any crown group. It is here considered as a member of the brachiopod stem group, which challenges recent interpretations of a close discinid affinity.  相似文献   

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