白洋淀白鲦鱼的生物学研究

本文对重新蓄水后白洋淀白鲦鱼的生物学特性进行了研究，经分析，发现群体中尤以１－１￣＋年龄个体比例最大，约占７３．９１％，反映出该种群正值恢复阶段，测定１６尾雌鱼，其平均怀卵量为１４９９４粒／尾，相对怀卵量１４４１粒／克体重，成熟系数最高达２６．３％，说明该种群繁殖力较强。因而，应保护其生存环境，有计划地捕获，以利于该种群得到快速恢复、发展。     

Relations between man and nature reflected by the evolution of the Neolithic production tools in the Three Gorges region of Yangtze River,China

The relations between man and nature reflected by evolution of Neolithic production tools in the Three Gorges region of Yangtze River is discussed in this paper.Our results show that there is a good correlation between the percentage vibration of cutting tool types and the environmental evolution indicated by the natural profile nearby.It is possible for ancestors from the Three Gorges region to learn the advantage of mortise and tenon in the early Neolithic Age because they used the stones as vital tools for processing woods.The hunting method in the early Neolithic is throwing,which was inherited in the mid-Neolithic Age when hunting with arrow and bow was developed.Fishing tools are found at the same period.Numbers of net sinkers and spinning wheels unearthed from the strata of the Western Zhou Dynasty from Zhongba Site reveal the fact of fishing with net,while a mass of fishbone pits indi- cate the powerful productivity brought by new production tools.Quantity of stone spades and stone hoes proves that cultivation agriculture by hoe is extremely attached importance by the ancestors in the Three Gorges region.Moreover,the developed agriculture in Daxi Culture at Zhongbao Island benefits from the landform,climate,traffic location,etc.Otherwise,the reason that the farming tools declined in the late Neolithic Age is related to the extreme flood during the early Xia Dynasty and the fishing hunting preference of some ancient settlements.This research shows that ancestors of the Three Gorges region during the Neolithic Age attached importance to fish hunting and cultivation, fought against the natural environment by production tools,constantly created and improved them, then comprehensively utilized them to evolve the relations between man and nature.     

Simulation of Greenland ice sheet during the mid-Pliocene warm period

One of the key uncertainties in future sea-level projections is attributed to the Greenland ice sheet(GrIS).Studying the response of the GrIS to climate changes during the past warm periods is helpful for understanding future changes in the GrIS.In this study,using three global climate models(Community Atmosphere Model version3.1 and version 4.0 and Norwegian Earth System Model)and a three-dimensional ice sheet model,we investigate the climate and ice sheet changes over Greenland during the mid-Pliocene warm period(*3 Ma BP).The results show that the regionally averaged summer temperature over Greenland is 9.4–13.4°C higher during the mid-Pliocene period than during the pre-industrial era and the annual mean precipitation is 65.2–108.3 mm a-1greater.In response to this warm-wet climate,the GrIS shows a substantial decrease in size during the mid-Pliocene,with little ice existing along the eastern coast of Greenland.Compared to that simulated in the control run,the global sea level is approximately 7.8–8.1 m higher during the mid-Pliocene due to the decrease in the size of the GrIS.In addition,paleoclimate proxies also indicate that it is unlikely that a large-scale ice sheet exists over Greenland during the mid-Pliocene warm period.     

关于“玉器时代”的再思考

在中国古代文化中,玉器文化因其丰富的内涵及玉器本身所蕴含的特殊观念而成为中国文化的特色之一。中国玉器文化产生于远古时期,发展时间甚为久远,而不同时期的玉器在各时期各地区文化中的地住和作用不尽相同。“玉器时代”一度成为人们重新划分古史分期的一个重要标准,学术界也就此特殊概念而掀起讨论热潮。总而言之,不论“玉器文化”是否可以作为某个时代的重要标志,它在中国古代社会中所产生的意义都是无法忽视的,尤其是在中国远古时期的某些地区,玉器对当地文化社会的发展曾起过至关重要的作用。     

浅谈小概率事件原理及其应用

小概率事件原理是概率论中一个基本且实用的原理。本文讨论了小概率事件及其相关性质,说明了小概率事件和不可能事件的区别与联系,并以实例说明小概率事件在概率论及假设检验中的实际应用。     

福建省阔叶林林分年龄与平均胸径、蓄积量的关系

根据福建省森林资源连续清查第5次复查资料,对750个天然阔叶林样地调查资料进行整理,通过χ2检验、剩余分析及log-线性模型的拟合,分析了天然阔叶林林分年龄与平均胸径、蓄积量之间的关系.结果 表明:χ2检验中林分平均胸径、蓄积量与林分年龄的连带关系明显;剩余分析中林分平均胸径、蓄积量随林分年龄的增长而呈现出增加的趋势,这与有序连带测定结果 基本一致,但主效应估计分析结果 与交互作用效应估计之间存在一定的差异,这种差异可能是由天然阔叶林受自身因素影响较多而受人为影响较少造成的.     

孤独之悲 孤独之美——解读《了不起的盖茨比》

小说《了不起的盖茨比》关注了主人公不同形式的孤独:盖茨比作为孤独的守望者,为了爱情和物质享受最后孤独死去;黛西在时代的影响下成为微笑的空灵者;尼克作为小说的叙述者,在面对各式孤独的过程中成为寂寞的求索者。他们与其他人物一起共同折射出战后爵士时代的精神困境。小说中的孤独具有时代性、艺术性和寓言性,提升了小说的深度与广度。     

Bathynotus --A key trilobite taxon? for global stratigraphic boundary correlation between Cambrian Series 2 and Series 3

The Cambrian trilobite Bathynotus is a special morphology of Redlichiid, which is characterized by a wider thorax axis and an 11th macropleural segment bearing a long, backwardly directed spine. Additionally, its 12th and 13th pleural segments are narrow and they terminate at a fulcrum where they fuse together and to the posterior edge of the long macropleural spine. The genus is widely distributed, occurring in North America, Siberia, the Altay-Sayan fold belt of Russia, South China, the Tarim Basin of China, and Australia. It occurs primarily in deposits of the upper part of the continental slope, at the transition between stable platform settings and subsiding margins of the late Early Cambrian. Here, we recognize three species of Bathynotus from China, including B. holopygus which is widespread around the world. Although six species of Bathynotus have been reported from Siberia and the Altay-Sayan fold belt area of Russia, data presented here suggest that only three of these species are valid. Bathynotus exhibits a short geological range, with its first occurrence late in the unnamed Cambrian Series 2 and the last appearance datum of Bathynotus at the boundary of Cambrian Series 2 and Cambrian Series 3. The late appearance datum (LAD) of Bathynotus provides an important global stratigraphic marker of the boundary between Cambrian Series 2 and Cambrian Series 3.     

宜春杉木人工林管胞形态变异及其对材性的影响

<正>测量了不同海拔、树龄的杉木人工林的管胞形态特征,并初步研究了管胞长度与年轮宽度、晚材率、木材密度以及有关力学强度(顺纹抗压、抗弯强度)的相互关系。可利用管胞形态(长度、直径、胞壁厚度)区分成、幼龄材的界限范围。     

Atmospheric oscillations over the last millennium

The variations of global atmospheric oscillations over the last millennium, including the North Atlantic Oscillation (NAO), the North Pacific Oscillation (NPO) highly associated with the Pacific Decadal Oscillation (PDO), the Southern Oscillation (SO) and the Antarctic Oscillation (AAO), are studied and compared in this paper based on observations and reconstructed data. The cross correlation analysis of AAO, NAO and NPO shows that there is no significant relationship on interannual variation among them. However, the consistency on decadal variability is prominent. During A.D.1920–1940 and A.D.1980–2000, the positive (strong) phase was dominant and the negative (weak) one noticeable during A.D.1940–1980. In addition, the reconstructed atmospheric oscillations series demonstrate that the positive phase existed in the early of the last millennium for NAO and in the late of the last millennium for AAO, respectively; while it occurred in the mid-late of the last millennium for PDO and ENSO.