检索结果-南通市图书馆

Expected adult lifespan in tropical trees: Long-term matrix demography in a large plot

Forest Ecosystems 2022年第4期9卷 558-566页

作者： Richard Condit Morton Arboretum 4100 Illinois Rte.53LisleIL60532USA Institute for marine sciences University of CaliforniaSanta CruzUSA

Background: Documenting the entire lifetime of long-lived organisms requires splicing together short-term observations. Matrix demography provides a tool to calculate lifetime statistics, but large samples from juvenile to adult are needed, and few such studies have been done in tropical trees because high species diversity limits sample sizes. The 50-ha plot at Barro Colorado in Panama was designed to provide large samples, and with 30years of censuses, accurate population matrices can be ***: In 31 abundant species, I divided all individuals≥1 cm dbh into 4 or 5 size class in each of seven censuses. Movements of stems between size classes over two censuses are termed transitions, and I constructed complete transition matrices for each species. From the matrices, I derived analytic solutions for lifetime demographic statistics. Expected adult lifespan from the sapling stage was the key ***: Expected adult lifespan from the sapling stage varied 100-fold over the 31 species, from 0.5 to 50 years,and maturation time varied from 19 to nearly 200 years. Species with the highest growth rates also had high death rates, and theoretical calculations of reproductive lifespan show that the fast-growing pioneer species have short expected adult lifespans relative to the average slow-growing, shade-tolerant species. Within the slowgrowth category, however, there was high variation in expected adult lifespan, and several shade-tolerant species under-performed the pioneers in terms of adult ***: Analytical solutions from population matrices allow theoretical analyses that integrate short-term growth records into lifespans of tropical trees. The analyses suggest that pioneer species must reproduce more successfully than shade-tolerant species to persist in the Barro Colorado forest. My next goal is to incorporate seed production and germination into lifetime matrix demography to test this hypothesis.

关键词： Tree lifespan Tropical tree Matrix demography

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

EFFECTS OF METAL IONS ON THE CONFORMATIONAL CHANGES OF DNA

引用

Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 659-663页

作者： G. Q. Liu Y. Y. Meng S.H. Liu Y.H. Hu Laser life Science Institute South China Normal University Guangzhou 510631China department of Medical Oncology Cancer Center Sun Yat-sen University of Medical Sciences Guangzhou 510060 China

DNA takes on multi-different conformations such as A-, B-, C-, D- and Z-form. These conformations can transit to one another when DNA deposited in some metal ions solutions or when changing the concentrations of the same metal ions. Here, several major conformational transitions of DNA induced by metal ions under different environment were introduced and the mechanism of the interaction of metal ions with DNA was discuss in detail.

关键词： DNA conformation transition mechanism condensation

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

Manganese enhances the antitumor function of CD8^(+)T cells by inducing type I interferon production

引用

Cellular & Molecular Immunology 2021年第6期18卷 1571-1574页

作者： Yuan Song Yonghao Liu Huey Yee Teo Zuhairah Binte Hanafi Yu Mei Ying Zhu Yen Leong Chua Mengze Lv Zhengfan Jiang Haiyan Liu Immunology Programme Life Sciences Institute and Department of Microbiology and ImmunologyYong Loo Lin School of MedicineNational University of SingaporeSingapore117456Singapore Jill Roberts Institute for Research in Inflammatory Bowel Disease(JRI) Weill Cornell MedicineCornell UniversityNew YorkNYUSA Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education School of Life SciencesPeking UniversityBeijing100871China Peking-Tsinghua Center for life sciences Peking UniversityBeijing100871China

The presence of cytosolic DNA at tumor sites and the activation of the cGAS-STING pathway have been implicated in the activation of antitumor immune responses.1,2,3 Manganese (Mn) is a necessary trace element for intracellular activities. It plays important roles in development, digestion, reproduction, antioxidant defense, energy production, immunity, and neuronal activity regulation.4 Mn was reported to enhance cGAS-STING activation through increased sensitivity to dsDNA during viral infections.5 However, it is unclear whether Mn can enhance antitumor immune functions. Here, we revealed that Mn2+ could inhibit the development of murine hepatocellular carcinoma (HCC) through immune modulations. It upregulated IFN-γ and TNF-α production in splenic and tumor-infiltrating CD8+ T cells. Moreover, Mn2+ significantly increased type I interferon (IFN) production and type I IFN-stimulated gene (ISG) expression in tumor-bearing mice. Further analysis revealed that myeloid cells could upregulate type I IFN production and increase costimulatory molecule expression upon Mn2+ stimulation. In vivo depletion of CD8+ T cells or treatment of IFNAR KO mice diminished the antitumor activity of Mn2+, suggesting that the antitumor function of Mn2+ is dependent on both CD8+ T cells and type I IFN signaling. Our results provide evidence to support Mn2+ as a novel agent that can be incorporated into cancer immunotherapy.

关键词： immunity interferon function

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

Monitoring open water area changes in a small tarn using historical orthophotomaps and a historical bathymetric map:a case study of the Litworowy Staw lake,the High Tatras

引用

Journal of Mountain Science 2018年第10期15卷 2089-2102页

作者： Juraj KAPUSTA Frantisek PETROVIC Juraj HRESKO department of Ecology and Environmental sciences Faculty of Natural SciencesConstantine the Philosopher UniversityNitraSlovakia

According to scientific evidence in general, the disappearance of the Tatras tarns as a result of external geomorphological processes has been accepted since the long term analyses of lake sediments and peat bogs, geomorphological mapping, geophysical measurements(– all indirect methods). It is paradoxical that the direct cartographic evidence of such changes has not existed until now. In this paper, we evaluate shore line changes of the small mountain glacial lake in the High Tatras-Litworowy Staw lake using a multitemporal analysis of a series of historical orthophotomaps and a historical map. Over the last 100 years, the tarn has lost 46.4% of open water level area. Significant visual changes were caused by vegetation growth of Carex species(sedges) on the water's surface. The accumulation of fine sediments and dead plant residues in the tarn basin create suitable conditions for this process, all together causing the tarn to become more shallow.

关键词： Vegetation growth of tarns Monitoring of changes Alpine lakes The High Tatras The Litworowy Staw lake

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

IN SITU DAILY GROWTH RATE OF PROCHLOROCOCCUS AT THE CHLOROPHYLL MAXIMUM LAYER IN THE SOUTHERN SOUTH CHINA SEA:AN ESTIMATION FROM CELL CYCLE ANALYSIS

引用

Chinese Journal of Oceanology and Limnology 2002年第S1期20卷 8-14页

作者：杨燕辉焦念志 Ministry of Education Key Laboratory for marine Environmental sciences Center of Marine Environmental Science Xiamen University Xiamen 361005 China

Prochlorococcus is the dominant population of the autotrophs in the oceanic area in theSouth China Sea; and contributes significantly to picoplanktonic (<2μm) carbon biomass. However, thereis no availabe data on its growth the and productivity so far. In the present study, the in situ populationgrowth rate of Prochlorococus at the chlorophyll maximum layer at 6 .3°N, 110°E in the South China

关键词： cell cycle Prochlorococcus growth rate the 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

Coagulation Mechanisms during the Substitution of Inorganic Salts with Cationic Polymers to Increase the Sludge Value

引用

Journal of Water Resource and Protection 2015年第17期7卷 1495-1501页

作者： Lelum Duminda Manamperuma Harsha Chandima Ratnaweera department of Mathematical sciences and Technology Norwegian University of Life Sciences Aas Norway

Phosphorus in wastewater sludge is a valuable resource although coagulated sludge reported to give only 10% of plant availability of phosphates. Since all Al and Fe added as coagulants end up in sludge, the potential to substitute them with cationic coagulants was studied. During combined coagulation, substitution possibilities up to 44% were observed with low coagulant-to-particle ratio where the adsorption-charge neutralisation (ACN) anticipated being the predominant mechanism. Comparatively high coagulant-to-particle ratio preferred Sweep-floc mechanism giving <20% substitution possibilities, though even lower values anticipated at higher phosphate removals. The cationic polymers’ ability to compete with positively charged Al- and Fe-hydrolysis products was argued as the explanation for higher substitution possibilities during ACN mechanism. Sub-stitutions can be enhanced with dual coagulation with intermediate sludge separation by avoiding competition between two coagulants.

关键词： Organic Polymers Inorganic Coagulants Plant Availability of Phosphorus Phosphorus Removal Coagulation Mechanisms

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

Influence of chromium on the initial corrosion behavior of low alloy steels in the CO_2–O_2–H_2S–SO_2 wet–dry corrosion environment of cargo oil tankers

引用

International Journal of Minerals,Metallurgy and Materials 2015年第8期22卷 829-841页

作者： Qing-he Zhao Wei Liu Jie Zhao Dong Zhang Peng-cheng Liu Min-xu Lu Institute for Advanced Materials and Technology University of Science and Technology Beijing marine Product Management department China Classification Society Headquarters

The influence of Cr on the initial corrosion behavior of low-alloy steels exposed to a CO2–O2–H2S–SO2 wet–dry corrosion environment was investigated using weight-loss measurements, scanning electron microscopy, N2 adsorption tests, X-ray diffraction analysis, and electrochemical impedance spectroscopy. The results show that the corrosion rate increases with increasing Cr content in samples subjected to corrosion for 21 d. However, the rust grain size decreases, its specific surface area increases, and it becomes more compact and denser with increasing Cr content, which indicates the enhanced protectivity of the rust. The results of charge transfer resistance(Rct) calculations indicate that higher Cr contents can accelerate the corrosion during the first 7 d and promote the formation of the enhanced protective inner rust after 14 d; the formed protective inner rust is responsible for the greater corrosion resistance during long-term exposure.

关键词： low alloy steels corrosion rate chromium rust oil

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

Response of phytoplankton to multispecies mariculture:a case study on the carrying capacity of shellfish in the Sanggou Bay in China

引用

Acta Oceanologica Sinica 2008年第1期27卷 102-112页

作者： GE Changzi FANG Jianguang SONG Xiefa MAO Yuze YE Naihao department of marine Fishery Ocean University of China Qingdao 266003 China Key Laboratory for Sustainable Utilization of marine Fishery Resource Yellow Sea Fisheries Research Institute Qingdao266071 China

A muhispecies model for shellfish polycuhure in the Sanggou Bay in China used for large-scale long-line cultivation of the Chinese scallop Chlamysfarreri, the Pacific oyster Crassostrea gigas and the kelp Laminaria japonica is presented. The model includes key physical processes which are the transports of matter at the system boundary, and the main biological process that is the primary production and nutrients release from the bottom. By the model, the seasonal fluctuations of phytoplankton biomass and dissolved inorganic nitrogen（DIN） in 1994 are simulated. Furthermore, if the kelp culture scale is kept constant and the Chinese scallop and the Pacific oyster culture scales are adjusted, virtual shellfish farms are funded and responses of phytoplankton to the largescale shellfish culture are simulated. According to these simulated results, the room limitation, and the hypothesis that shellfish will not grow well if the phytoplankton biomass is less than 8.2 mg/m^3 , the expandable multiple of scallop culture k and that of oyster culture y are determined as k = -0.276 5y ＋4.690 5 and 0.133 3k ＋0.006 6y≤0.667 5, where, k （ or y） is equal to 1, the culture scale of scallop （ or oyster） is 8.8 x 109 individuals （or 66 ha, with a density of 59 ind./m^2 ）, and the kelp culture scale is 3 300 ha with a density of 12 ind./m^2.

关键词： multispecies model kelp Chinese scallop Pacific oyster carrying capacity

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 positivity of high-degree Schur classes of an ample vector bundle

引用

Science China Mathematics 2022年第1期65卷 51-62页

作者： Jian Xiao department of Mathematical sciences and Yau Mathematical sciences Center Tsinghua UniversityBeijing 100084China

Let X be a smooth projective variety of dimension n,and let E be an ample vector bundle over *** show that any Schur class of E,lying in the cohomology group of bidegree(n-1,n-1),has a representative which is strictly positive in the sense of smooth *** conforms the prediction of Griffiths conjecture on the positive polynomials of Chern classes/forms of an ample vector bundle on the form level,and thus strengthens the celebrated positivity results of Fulton and Lazarsfeld(1983)for certain degrees.

关键词： ample vector bundles Griffiths conjecture positive polynomials Schur classes

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

MEMBRANE POTENTIAL——A KEY PARAMETER OF AQUATIC MICROPLANKTON

引用

Chinese Journal of Oceanology and Limnology 2002年第S1期20卷 74-80页

作者：杨印杰焦念志 Ministry of Education Key Laboratory for marine Environmental sciences Center of Marine Environmental Science Xiamen University Xiamen 361005 China

Membrane potential is essential for the uptake of substance and physiological activityin cells; and is an indicator of cell viability and a criterion of aquatic environment. It is also applied toclassification of ecological populations. So membrane potential is a key parameter in studies on aquaticmicroplankton. It can be estimated by microelectrode, radioisotope method, spectro photomeny, flow cy-

关键词： membrane potential aquatic microplankton flow cytometry

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

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：