鸟类后肢上的羽毛揭开古鸟类短尾之谜

今年l0月21日出版的英国《自然》杂志发表了中国科学院古脊椎动物与古人类研究所张福成和周忠和的一篇有关古鸟类飞行的文章。在这篇题为《一早白垩世鸟类的腿羽》的论文中，两位专家报道了一只生活在1．2亿年前的既保存有完好的腿羽又保存有短的尾羽的鸟类化石。该鸟腿部的羽毛可能帮助揭开原始鸟类的“短尾”之谜，同时也进一步支持了鸟类飞行演化经历了“四个翅膀”阶段的假说。     

春小麦适期早播增产分析

本文在搜集整理春小麦适期早播材料的基础上,通过小区试验,对其植株器官建成,产量结构等性状的特点进行了较系统的观察,对适期早播增产原因作了初步分析。     

雷州半岛中晚全新世造礁珊瑚Sr/Ca比值的表层海水温度记录

通过分析两个取自雷州半岛南部的全新世珊瑚的高分辨率Sr/Ca比值,重建了这两个历史时期(公元489～500年和公元前539～530年)月平均分辨率的表层海水温度记录.结果显示,公元前539～530年时段表层海水温度(SST)与现代基本相同,代表相对温暖的气候;而公元489～500年时段10年平均的冬、夏季SST与现代器测记录相比分别低2.9和l℃,年均温度低2℃左右,代表相对寒冷的气候.这些珊瑚记录的气候特征与中国其他地区根据物候及历史记录获得的气候记录相吻合.     

《饮酒》:陶渊明的审美化人生哲学

陶渊明的《饮酒》实际上包含了“忘世”、“忘我”、“忘言”三个层次,指向的是一种审美化人生哲学的建立和体验。     

Characteristics of seismostratigraphy and analysis of structurallithofacies in the southern Yellow Sea Cenozoic basin

In this paper,the upper structural layer of the southern Yellow Sea Basin (SYSB) is further divided into three layers based on the latest obtained high-resolution single-channel seismic profiles.Combined with the borehole data,the characteristics and evolvement of structure and environment since middle-late Tertiary are discussed.The study shows that the acoustic-base indicated by shallow seismic profiles represents the basic shape of the SYSB in late Oligocene-early Miocene.Based on the comprehensive analysis of some typical profiles crossing the basin about seismostratigraphy,gravity and magnetics,the basin about seismostratigraphy,gravity and magnetics,the basin edge fault and some basin inner structure are identified.Furthermore,the acoustic-base is classified into four types of basal lithofacies:Eogene basin basement,Paleozoic basement,Mesozoic basement and magma intrusion basement.     

金红苹果矮化密植栽培技术

金红苹果矮化密植栽培，比乔化栽培密度增加一倍到两倍，亩株数达到80～110株以上。具有结果早、产量高、品质好、树体矮小、管理方便、经济利用土地、单位面积效益高等特点。现将适合乌兰察布地区金红苹果矮化密植栽培技术措施介绍如下：     

贵州关岭三叠系中一奇特的楯齿龙类

记述了产自贵州省关岭县法郎组瓦窑段一豆齿龙类新属种--多板砾甲龟龙(Psephochelys polyosteoderma gen et sp nov). 标本为完整的头骨、背甲和部分四肢骨骼. 砾甲龟龙的头骨综合体现了欧洲Psephoderma和Placochelys两个属的共同特征, 而背甲和腹部的结构则完全与众不同. 砾甲龟龙的腹部由分布于两侧部分的一系列松散的长形骨板和中部的密集的腹肋组成, 这种结构是任何其他豆齿龙所不具备的. 另外, 该标本头骨中部的一些结构十分奇特, 目前还很难对其作出确定的解释. 这些结构主要涉及鼻骨与前额骨的界限以及额骨、后额骨与顶骨三者间的关系. 就目前的标本看, 砾甲龟龙的后额骨参与组成颞孔的前缘, 这是楯齿龙亚目(Placodontoidea)中Placodus的特征, 此前从未在豆齿龙亚目(Cyamodontoidea)中被记录过. 这些罕见特征的最终确立还有待于更多标本来加以证实.     

Composition of plagioclase in Dabie Early Cretaceous granitoids:influence of fractional crystallization on whole-rock Sr–Ca O correlations

Identifying melts of thickened lower continental crust from high Sr/Y rocks is very important to trace deep crustal processes. Recent studies on Dabie Early Cretaceous granitoids have revealed that melts derived from thickened lower continental crust have higher Sr/CaO ratios and define a high Sr evolution trend compared with normal granitoids. Fractional crystallization of plagioclase can significantly change Sr and CaO contents of melts, but its role in controlling the Sr/CaO ratios of the melts is still unclear. This study gives a direct comparison of plagioclase compositions between normal granitoids and low-Mg adakitic rocks. On the basis of Sr-Ca exchange partition coefficient, discussions on effect of plagioclase crystallization on Sr/CaO ratios of melts show that fractional crystallization of abundant plagioclase cannot significantly change Sr/CaO ratios of granitic melts, which are inherited from their individual initial melts. High Sr/CaO ratios indicate the absence of plagioclase in sources of granitic melts. Therefore, high Sr/CaO correlation can be an important indicator to identify melts derived from thickened lower continental crust.