检索结果-南通市图书馆

The first pterosaur 3-D egg:Implications for Pterodaustro guinazui nesting strategies,an Albian filter feeder pterosaur from central Argentina

引用

Geoscience Frontiers 2014年第6期5卷 759-765页

作者： Gerald Grellet-Tinner Michael B.Thompson Lucas E.Fiorelli Eloísa Argaaraz Laura Codorniú E.Martín Hechenleitner Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR-CONICET) Entre Ríos y Mendoza s/nAnillaco5301 La RiojaArgentina orcas island historical museums USA School of Biological Sciences (A08) University of SydneyNSW 2006Australia CONICET Argentina Centro de Investigaciones Paleobiológicas (CIPAL) Universidad Nacional de CórdobaAv.Vélez Sarsfield 2995000 CórdobaArgentina Departamento de Geología Universidad Nacional de San LuisSan LuisArgentina

The increasing number of fossil pterosaur eggs sheds light on nesting environments and breeding be- haviors of these extinct flying reptiles. Here we report the first partial three-dimensional egg of the pterosaur, Pteroduustro guinazui, from central Argentina. The specimen was discovered from the same Albian deposits as the exceptional R guinazui embryo described in 2004. Microscopic characterizations indicate a pristine preservation of the 50 Bm thick calcium carbonate, which differs significantly from the soft shell of Chinese pterosaur eggs. Estimate of the eggshell conductance implies that the nest had a minimum moisture content of 75%. This moisture estimate, combined with geological and taphonomical data, suggests that P. guinazui may have adopted a nesting strategy similar to those of grebes and flamingos rather than being buried on land, as previously hypothesized. Moreover, our results demon- strate that the nesting paleoenvironment of this pterosaur species was closely linked to a mesohaline lacustrine ecosystem in a basin governed by regional tectonic subsidence, a setting characteristic for the feeding and reproduction of modern flamingos.

关键词： Pterosaur fossil eggsPterosaur eggshellPterodaustro guinazuiGondwanaEggshell conductance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Environmental changes during modern period from the record of Gaoyou Lake sediments, Jiangsu

引用

Journal of Geographical Sciences 2007年第1期17卷 62-72页

作者： LI Shuheng FU Guanghe GUO Wei HE Huachun ZHANG Zhenke The Key Laboratory of Coast ＆ island Development of Ministry of Education Nanjing University Nanjing 210093 China

Based on analysis of parameters of cores taken from Gaoyou Lake, including magnetic susceptibility, grain-size characteristics and sedimentary rate, environmental changes during the modern period were examined with the assistance of historical records and Gaoyou Lake water level materials. It is concluded that during the modern period a higher value of magnetic susceptibility and a lower sediment grain size coincided with a wet climate, while a lower value of magnetic susceptibility and a higher grain size were related with a dry climate. The results indicate that the climate in the 123 years period from 1880 to 2003AD can be divided into four stages： two low water level stages （1880-1915AD, 1948-1981AD） and two high water level stages （1915-1948AD, 1981-2003AD）. It appears that the regional climate generally underwent a dry-wet-dry-wet pattern in 30-year cycles. At present, it is at the end of a wet period, so the regional climate is expected to become dry in the near future. This conclusion corresponds with the climate records in the historical literature of the Gaoyou area, and it also matches with the climatic changes in North Jiangsu area.

关键词： Gaoyou Lake environmental changes lake sediments

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Typhoon events recorded in coastal lagoon deposits,southeastern Hainan island

引用

Acta Oceanologica Sinica 2017年第4期36卷 37-45页

作者： ZHOU Liang GAO Shu YANG Yang ZHAO Yangyang HAN Zhuochen LI Gaocong JIA Peihong YIN Yong ing 210093 China Ministry of Education Key Laboratory for Coast and island Development Nanjing University Nanjing 210093 China

Coastal lagoon deposits provide evidence for the magnitude and frequency of past tropical cyclones prior to instrumental records and historical *** the present study,we attempt to analyze the sedimentary records containing typhoon information for the northern South China Sea *** this purpose,sediment cores were collected from two coastal lagoons in the southeastern Hainan island,and were analyzed in laboratory to derive the data sets about grain size,organic and inorganic carbon contents,and deposition *** grain size and organic-inorganic carbon data were used to formulate the proxies of typhoon *** deposition rates,as calculated using the CRS 210 Pb method,are around 0.5 mm/a for both lagoons,on the basis of which an age model is *** the cores,sedimentary layers associated with 35 typhoon events have been *** such a basis,a 350 year history of local typhoon activities is reconstructed by incorporating the 210 Pb dating results,typhoon-induced sedimentation patterns and the historical documents.A comparison of the frequency of typhoon occurrence with the regional climate records indicates that the observed changes in tropical cyclone activity patterns,as revealed by the lagoon sedimentary records,may be related to El Ni？o,Pacific Decadal Oscillation（PDO）,North Atlantic Oscillation（NAO）,sunspot,and other potential climate drivers that affect the tropical cyclone *** study demonstrates that the sedimentary record of storms can be analyzed in combination with historical documents,to provide meaningful information on past storm activities and their long-term variability.

关键词： paleostorms typhoon-induced deposits grain size loss on ignition Hainan island

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On the sediment age estimated by ^(210)Pb dating: probably misleading “prolonging” and multiple-factor-caused “loss”

引用

Acta Oceanologica Sinica 2018年第6期37卷 30-39页

作者： JIA Jianjun YANG Yang CAI Tinglu GAO Jianhua XIA Xiaoming LI Yan GAO Shu State Key Laboratory of Estuarine and Coastal Research East China Normal University Key Laboratory of Coast and island Development of MOE Nanjing University State Research Centre for island Exploitation and Management Second Institute of Oceanography State Oceanic Administration College of the Environment and Ecology Xiamen University

The radionuclide ^（210） Pb is suitable for century-scale dating and has been used to calculate the sedimentation rate in a variety of environments. However, two common ways to apply 210 Pb dating techniques may give misleading results. One is ＂prolonging of age＂, i.e., using the calculated sedimentation rate to date back to 200 or 300 *** practice must be treated with caution because the 210 Pb dating techniques do not guarantee direct dating for ages much older than 100 years. Another is ＂loss of age＂, i.e., the calculated time span between the topmost layer and the 210 Pb background layer in cores is less than 100 years when an apparent sedimentation rate is used in the calculation. Here, we propose that based on the principle of 210 Pb dating, the upper limit of age suitable for direct210 Pb dating is between 110 and 155 years. The ＂prolonging＂ application is acceptable only if the sedimentary environment in the past several hundred years was stable and the sedimentation rate was generally constant, and verification with independent evidence（such as historical records or biomarker methodology） is ***, after analyzing many published and collected data, we found four possible reasons for the ＂loss of age＂. First, the compaction effect of sediment should be corrected in laboratory analysis or else the calculated age will be underestimated. Second, the accuracy and uncertainty of 210 Pb activity measurement affect the judgment of the background. To be cautious, researchers are apt to choose a background activity with a younger age. Third,use of a slightly smaller value of supported 210 Pb activity in a calculation will lead to considerable underestimation of the time span. Finally, later-stage erosion and migration are common for sedimentation, which lead to loss of sedimentary records and are often reflected as a ＂loss of age＂ in cores. We believe that proper use of 210 Pb dating data may provide helpful information on our understanding of sedi

关键词： ^210Pb dating sedimentation rate sediment flux

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Rapid dynamical pattern recognition for sampling sequences

引用

Science China(Information Sciences) 2021年第3期64卷 118-135页

作者： Weiming WU Qian WANG Chengzhi YUAN Cong WANG School of Automation Science and Engineering South China University of Technology School of Control Science and Engineering Shandong University Department of Mechanical Industrial and Systems Engineering University of Rhode Island

In this paper, based on deterministic learning, we propose a method for rapid recognition of dynamical patterns consisting of sampling sequences. First, for the sequences yielded by sampling a periodic or recurrent trajectory(a dynamical pattern) generated from a nonlinear dynamical system, a sampled-data deterministic learning algorithm is employed for modeling/identification of inherent system dynamics. Second,a definition is formulated to characterize similarities between sampling sequences(dynamical patterns) based on differences in the system dynamics. Third, by constructing a set of discrete-time dynamical estimators based on the learned knowledge, similarities between the test and training patterns are measured by using the average L1 norms of synchronization errors, and general conditions for accurate and rapid recognition of dynamical patterns are given in a sampled-data framework. Finally, numerical examples are discussed to illustrate the effectiveness of the proposed method. We demonstrate that not only a test pattern can be rapidly recognized corresponding to a similar training pattern, but also the proposed recognition conditions can be verified step by step based on historical sampling data. This makes a distinction compared with the previous work on rapid dynamical pattern recognition for continuous-time nonlinear systems, in which the recognition conditions are difficult to be verified by using continuous-time signals.

关键词： deterministic learning dynamical pattern recognition sampling sequence synchronization

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Are trends in SeaWiFS chlorophyll time-series unusual relative to historic variability

引用

Acta Oceanologica Sinica 2010年第2期29卷 1-4页

作者： James A Yoder Maureen A Kennelly Scott C Doney Ivan D Lima Woods Hole Oceanographic Institution Woods Hole MA 02540 USA Graduate School of Oceanography University of Rhode island Narragansett RI 02882 USA

For selected locations in the Atlantic and Pacific Ocean, we compared surface ocean chlorophyll time series extracted from SeaWiFS imagery from 1997-2004 with the results of an ocean coupled circulation and biogeochemical model covering the period 1958-2004. During the 1997-2004 time period, linear trends in model and satellite time series were significantly correlated at most of the 44 sites we studied. Eleven sites were selected for further study, and we used the longer time series of the model to assess whether trends observed during the SeaWiFS period at these 11 sites were unusual in relation to those observed over the longer historical period covered by the model. The results show that the trends observed during the SeaWiFS period were not unusual and fell well within the range in magnitude of linear trends observed in other 8-year periods of model output. This result implies that the SeaWiFS satellite ocean color time series is not yet sufficiently long, on its own, to directly observe any long term changes in phytoplankton chlorophyll that may be occurring in the surface waters of the open ocean as a result of increased ocean stratification linked to global climate changed.

关键词： SeaWiFS trends climate change chlorophyll biogeochemical model ENSO

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Rapid changes of sediment dynamic processes in Yalu River Estuary under anthropogenic impacts

引用

International Journal of Sediment Research 2012年第1期27卷 37-49页

作者： Jian-hua GAO Jun LI Harry WANG Fen-long BAI Yan CHENG Ya-ping WANG Key Laboratory for Coast and island Development of Ministry of Education Nanjing University Qingdao Institute of Marine Geology Virginia Institute of Marine Science Gloucester PointVA 23062United States Prof. School of Urban Construction East Liaoning University 5. Key Laboratory for Coast and Island DevelopmentMinistry of EducationNanjing University

The response of the Yalu River Estuary to human activities was *** of sediment dynamics during the past 10 years were explored through hydrodynamic calculation,as well as heavy mineral and grain size *** addition,the characteristics of estuarine geomorphological evolution were compared with historical *** long-term sediment dynamic process and geomorphological evolution were primarily affected by the decrease of water discharge and sediment supply resulting from human *** entire estuarine system of Yalu River Estuary has also undergone significant changes since 1941 that are associated with water reduction and sediment discharge affected by construction *** estuary eventually formed the current patterns in the *** with variations of water and sediment discharge,sand dredging directly affected the estuarine sediment dynamics in the past 10 *** from six hydrodynamic stations measured in 2009 indicated that the bedload transport flux has substantially decreased during a tidal cycle compared with that surveyed in *** bedload transport direction also changed from seaward in 1996 to landward in *** addition,the estuarine bed load movement changes were:(a) sediment from areas with water depth being less than 5 m was transported from the sea towards the land;(b) sediment transport from areas with water depth between 5 to 20 m was oriented towards the sea;and (c) sediment from areas with water depth greater than 20 m was conveyed from the sea towards the land.

关键词： Sediment dynamics Geomorphology Human activities Yalu River Estuary

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Two centuries of April-July temperature change in southeastern China and its influence on grain productivity

引用

Science Bulletin 2017年第1期62卷 40-45页

作者： Jiangfeng Shi Jinbao Li David D.Zhang Jingyun Zheng Shiyuan Shi Quansheng Ge Harry F.Lee Yesi Zhao Jie Zhang Huayu Lu Ministry of Education Key Laboratory for Coast and island Development School of Geographic and Oceanographic Sciences Nanjing University Department of Geography University of Hong Kong Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

China is a traditional agriculture based country and one main region for crop production is southeastern China where temperature is a dominant climate variable affecting agriculture. Temperature and social disturbances both influence crop production, yet distinguishing their relative impacts is difficult due to a lack of reliable, high-resolution historical climatic records before the very recent period. Here we present the first tree-ring based warm-season temperature reconstruction for southeastern China, a core region of the East Asian monsoon, for the past 227 years. The reconstruction target was April-July mean temperature, and our model explained 60.6% of the observed temperature variance during 1953–*** correlation analysis showed that the reconstruction is representative of April-July temperature change over most of eastern China. The reconstructed temperature series agrees well with China-scale(heavily weighted in eastern China) agricultural production index values quite well at decadal *** impacts of social upheavals on food production, such as those in the period 1920–1949, were confirmed after climatic influences were excluded. Our study should help distinguish the influence of social disturbance and warm-season temperature on grain productivity in the core agricultural region of China during the past two centuries.

关键词： Temperature Grain productivity Social disturbance China Tree-rings

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Evidence of China's sea boundary in the South China Sea

引用

Acta Oceanologica Sinica 2017年第4期36卷 1-12页

作者： WANG Ying GE Chendong ZOU Xinqing Collaborative Innovation Center of South China Sea Studies Nanjing University Nanjing 210023 China Ministry of Education Key Laboratory for Coast and island Development Nanjing University Nanjing 210023 China

According to a series of important historical maps,i.e.,the Location Map of the South China Sea islands,the Nansha islands,Zhongsha islands,Xisha islands,Yongxing island and Shidao island,and Taiping island（archived by the Territorial Administration Division of the Ministry of Interior of Republic of China in 1946）,and the Administration District Map of the Republic of China published in 1948,the dashed line surrounding the South China Sea islands represents China＇s sea boundary in the South China Sea at that *** was both connected with,and an extension of,the land boundary of *** that time the dashed line was used to represent the waters boundaries while the solid line was used to represent the land boundary—a universal method used in maps that was then recognized *** above observation provides historical and scientific evidence of China＇s sea boundary in the South China Sea that is useful for the international maritime delimitation over the South China Sea area.

关键词： China's sea boundary historical maps maritime sovereignty South China Sea

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Physical Laws and Mathematical Axioms of the Brain’s OS and the Traditional Fundamental Laws of Thought of Logic and Philosophy

引用

Advances in Pure Mathematics 2021年第12期11卷 988-1039页

作者： Leo Depuydt Department of Egyptology and Assyriology Brown University Providence Rhode Island USA

This article presents four (4) additions to a book on the brain’s OS published by SciRP in 2015 [1]. It is a kind of appendix to the book. Some familiarity with the earlier book is presupposed. The book itself proposes a complete physical and mathematical blueprint of the brain’s OS. A first addition to the book (see Chapters 5 to 10 below) concerns the relation between the afore-mentioned blueprint and the more than 2000-year-old so-called fundamental laws of thought of logic and philosophy, which came to be viewed as being three (3) in number, namely the laws of 1) Identity, 2) Contradiction, and 3) the Excluded Middle. The blueprint and the laws cannot both be the final foundation of the brain’s OS. The design of the present paper is to interpret the laws in strictly mathematical terms in light of the blueprint. This addition constitutes the bulk of the present article. Chapters 5 to 8 set the stage. Chapters 9 and 10 present a detailed mathematical analysis of the laws. A second addition to the book (Chapter 11) concerns the distinction between the laws and the axioms of the brain’s OS. Laws are part of physics. Axioms are part of mathematics. Since the theory of the brain’s OS involves both physics and mathematics, it exhibits both laws and axioms. A third addition (Chapter 12) to the book involves an additional flavor of digitality in the brain’s OS. In the book, there are five (5). But brain chemistry requires a sixth. It will be called Existence Digitality. A fourth addition (Chapter 13) concerns reflections on the role of imagination in theories of physics in light of the ignorance of deeper causes. Chapters 1 to 4 present preliminary matter, for the most part a brief survey of general concepts derived from what is in the book [1]. Some historical notes are gathered at the end in Chapter 14.

关键词： Aristotle Boole G. Brain’s OS Fundamental Laws of Thought Kolmogorov A. N. Laws and Axioms Leibniz G. W. Locke J. Logic Philosophy Rational Human Intelligence Venn J.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：