检索结果-南通市图书馆

Neutron Activation Analysis and Scanning Electron microscopy of Phytoplankton in the Coastal Zone of Crimea (The Black Sea)

引用

American Journal of Analytical Chemistry 2014年第5期5卷 323-334页

作者： P. S. Nekhoroshkov A. V. Kravtsova m. V. Frontasyeva Yu. N. Tokarev Department of Biophysical Ecology Department of Biotechnology and Phytoresources The A.O. Kovalevsky Institute of Biology of the Southern Seas of the National Academy of Science of the Ukraine Sevastopol Ukraine Sector of Neutron Activation Analysis and Applied Research The Frank Laboratory of Neutron Physics Joint Institute for Nuclear Research Dubna Russia

The physiology and ecology of planktonic organisms are influenced by the concentration, chemical speciation and resulting bioavailability of some trace metals. The determination of the elemental structure of phytoplankton is important for interpretation of physiological and functional states of coastal ecosystems. The present study is focused on the structure and elemental composition of the phytoplankton assemblages from the different coastal zones by instrumental neutron activation analysis (INAA), scanning electron microscopy (SEm) and energy-dispersive X-ray spectrometry (EDS). For the first time these complementary techniques were simultaneously applied to study the Black Sea phytoplankton. The concentrations of 45 elements in the coastal phytoplankton communities used as bioindicator of inorganic contamination of the Black Sea coastal area near Sevastopol, Ukraine, were determined. Phytoplankton samples were collected by total tows of the plankton net with 35 μm pore size at 3 stations situated in polluted and relatively pristine water areas of the Sevastopol coastal zone during autumn period of the phytoplankton growth. The concentration of mg, Al, Sc, Ti, V, mn, As, Rb, Ba, Th and Fe, Cr increases exponentially from relatively pristine station to more polluted station and 10-times and 3-times greater, respectively, in the phytoplankton of the Sevastopol Bay. The rare-earth elements have relatively the same concentration values less than 1 μg/g and tend to accumulate in the phytoplankton from the polluted station in the Sevastopol Bay. The obtained results are in a good agreement with the elemental concentration data in the oceanic plankton, plankton communities from the White Sea and the Black Sea. Using energy-dispersive X-ray spectrometry the mineral particles of unknown origin and impurities of copper (0.42% by weight) in the phytoplankton at the polluted station and zinc (0.57% by weight) at the relatively pristine station were determined.

关键词： Black Sea Phytoplankton Scanning Electron microscopy Neutron Activation Analysis Energy-Dispersive X-Ray Spectrometry Trace Elements

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

Wind Field in Greater Tehran Area (GTA) in autumn Season

引用

Journal of Thermal Science 2000年第3期9卷 205-210页

作者： Kh. Badii B. Dabir N.S. moussiopoulos P. Sahm S.m. Alaie Th. Nitis (Chemical Engineering Department, Amir-Kabir University of Technology, Hafez Ave., Tehran, Iran. mechanical Engineering Department, Aristotle University of Thessalonild, Thessaloniki, Chemical Engineering Department Amir-Kabir University of Technology Tehran Iran mechanical Engineering Department Aristotle University of Thessaloniki Thessaloniki Greece

Air Pollution is one of the main contaminants in industrial cities like Tehran, but it depends on many factors. One of the most important factors is wind field. Wind field shows how the pollutants transfer by convective mechanism. Tehran as the most polluted city of Iran (or may be middle East) locates in a mountainous situation and is surrounded from two sides by high mountains and from two sides by desert. Therefore, the topography of Greater Tehran Area is so complex and needs more attention. We have studied the air pollution in Tehran from this point of view in this paper and used mEmO software for simulation of wind field in this area. The results show good agreement with experimental observations and show stronger wind from south to north and west-south to east-north in days and then night in reverse direction. It causes that the pollutants remain at urban area and the concentrations of pollutants reach to a serious level.

关键词： wind field air pollution inversion modelling mEmO software.

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

吉林长白山北坡天然林鼠害调查

引用

四川动物 2017年第3期36卷 341-345页

作者：娄昆施玉华张义锋朴正吉肖治术路纪琪 ALFRED m Sichilima 王振龙郑州大学生命科学学院郑州450001 郑州大学生物多样性与生态学研究所郑州450001 长白山科学研究院吉林延边133613 中国科学院动物研究所、农业虫鼠害综合治理研究国家重点实验室北京100101 Department of Biological Sciences School of Mathematics&Natural SciencesCopperbelt UniversityP.O.Box 21692KitweZambia

吉林省长白山北坡天然林是我国重要的红松Pinus koraiensis种源基地,近年鼠害严重。2015年4—6月、9—10月,在阔叶林、针阔混交林、针叶林、暗针叶林及岳桦Betula ermanii林中调查鼠害发生情况,统计危害发生的树种和部位,并在危害发生... 详细信息

吉林省长白山北坡天然林是我国重要的红松Pinus koraiensis种源基地,近年鼠害严重。2015年4—6月、9—10月,在阔叶林、针阔混交林、针叶林、暗针叶林及岳桦Betula ermanii林中调查鼠害发生情况,统计危害发生的树种和部位,并在危害发生林型中采用笼捕法和陷阱法调查鼠类的组成。结果表明:1)鼠害主要发生在春季海拔800~1 100 m的针阔混交林;2)受害树种主要为椴树Tilia tuan(3.61%±1.05%)、假色槭Acer pseudo-sieboldianum(3.00%±0.63%)、红松(1.73%±0.31%)、色木槭***(1.28%±0.14%)等重要经济林木,受害部位主要集中于林木基部(58.90%)和裸露根部(37.99%);3)长白山北坡林区春季鼠类捕获率较高,秋季较低;4)捕获的主要鼠种为棕背myodes rufocanus、朝鲜姬鼠Apodemus peninsulae和红背***,陷阱法对棕背的捕获率远高于笼捕法,但对朝鲜姬鼠和红背的捕获率较笼捕法低。

关键词：长白山北坡天然林针阔混交林鼠害笼捕法陷阱法

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

modelling Agronomically-Suitable Sowing Date in Relation to the Risk of Frost Damage and Heat Stress of Wheat in Southern New South Wales, Australia

引用

Journal of Agricultural Science and Technology 2010年第4期4卷 26-36页

作者： D. L. Liu P. martin C. Cole H. Wu E. Wang A. m. Bowman E.H. Graham Centre for Agricultural Innovation （Industry ＆ Investment NSW and Charles Sturt University） Wagga Wagga Agricultural Institute Wagga Wagga NSW 2650 Australia NSW Department of Primary Industries Wagga Wagga Agricultural hzstitute Wagga Wagga NSW 2650 Australia CSIRO Land and Water GPO Box 1666 Canberra ACT2601 Australia

Sowing time of wheat in south eastern Australia varies from autumn to early winter, depending on the seasonal ＇break＇. Wheat yields are often reduced by frost damage at flowering time and by heat-and/or water-stress during grain filling. Selecting suitable varieties for specific sowing times is a complex decision farmers make because these varietal phenology and climate risks have to be assessed together. In order to help farmers make decisions, they need tools that simulate and analyse agronomically-suitable sowing dates （ASSD） for a given variety of wheat. The hypothesis underlining this study is the integration of a wheat phenology model with historical climate data is an effective approach to modelling the ASSD of current varieties used in the wheat growing areas of Southern NSW. The parameters of the wheat phenology model were based on data from five years of field experimentation across 15 sites. Data from four sites were used to examine varietal suitability in relation to sowing time and its associated risks of frost and heat damage. The optimum ASSD for any variety at 72 locations across Southern NSW was investigated. The results showed that there were substantial spatial variations in the ASSD across the target region. ASSD for a late maturing wheat genotype （EGA Gregory） can range from early march to late April, while the earliest acceptable sowing date for an early maturing spring wheat genotype （H46） can range from early to late may. The wide range of spatial variation in the earliest and latest sowing dates, as well as the varied length of sowing opportunities, highlighted the importance of being able to apply a modelling approach which can integrate information on crop phenology with climate risk for a given location. This approach would allow better decision-making on suitable varieties and sowing dates in order to minimise the risk of frost and heat damage affecting crop yield.

关键词： Crop phenology climate risk decision-making spatial variation break of season sowing opportunities

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

Effects of Sea Level Variation on Biological and Chemical Concentrations in a Coastal Upwelling Ecosystem

引用

Journal of Environmental Protection 2013年第11期4卷 61-76页

作者： marilia m.F.de Oliveira Gilberto C.Pereira Jorge L.F.de Oliveira Nelson F.F.Ebecken Civil Engineering Program Federal University of Rio de Janeiro-UFRJCenter of TechnologyFundao IslandRio de JaneiroBrazil Geography Postgraduate Program Fluminense Federal University-UFFGeoscience InstituteNiteroiBrazil

Oscillations in sea level due to meteorological forces related to wind and pressure affect the regular tides and modify the sea level conditions, mainly in restricted waters such as bays. Investigations surrounding these variations and the biological and chemical response are important for monitoring coastal regions mainly where upwelling shelf systems occur. A spatial and temporal database from Quick Scatterometer satellite vector wind, surface stations from the Southeast coast of Brazil and surface seawater data collected in Anjos Bay, Arraial do Cabo city, northeast of Rio de Janeiro State were used to investigate the meteorological influences in the variability of the dissolved oxygen, nutrients, meroplankton larvae and chlorophyll-a concentrations. multivariate statistical approaches such as Principal Component Analysis (PCA) and Clustering Analysis (CA) were applied to verify spatial and temporal variances. A correlation matrix was also verified for different water masses in order to identify the relationship between the above parameters. A seasonal variability of the meteorological residual presents a well-defined pattern with maximum peaks in autumn/winter and minimum during spring/summer with negative values, period of occurrence of upwelling in this region. This lowering of the sea level is in accordance with the increasing of nutrients and meroplankton larvae for the same period. CA showed six groups and an importance of the zonal and meridional wind variability, including these variables in a single cluster. PCA retained eight components, explaining 64.10% of the total variance of data set. Some clusters and loadings have the same variables, showing the importance of the sea-air interaction.

关键词： meroplankton Larvae Nutrient Concentrations Coastal Waters Brazilian Upwelling

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

Preliminary Study by Environmental Indicator measurements of Sediments in a mangrove Forest in Ilha Grande Bay,Rio de Janeiro,Southeastern Brazil

引用

Journal of Environmental Protection 2012年第8期3卷 731-739页

作者： Ana maria A.Velho Claudia A.F.Aiub Jose L.mazzei Sergio m.Correa mario L.G.Soares Israel Felzenszwalb Department of Biophysics and Biometry Institute of Biology Roberto Alcantara GomesRio de Janeiro State UniversityVila IsabelBrazil Departamento de Genetica e Biologia molecular Instituto BiomedicoUniversidade Federal do Estado do Rio de JaneiroCentroBrazil Department of Environmental Chemistry Institute of ChemistryRio de Janeiro State UniversityResendeBrazil Center for Research on mangroves Institute of OceanographyRio de Janeiro State UniversityMaracanaBrazil

mangroves perform essential functions in biological cycles and are protected by law in Brazil. However, they are being degraded above their support limit, leading to a reduction in the areas around the world. The area investigated in the present study is a potentially unpolluted mangrove ecosystem in the south of Rio de Janeiro state, Brazil. The aim of this work was to investigate the presence of metals and polycyclic aromatic hydrocarbons (PAHs) in mangrove sediment and to correlate them with mutagenic and genotoxic activity. Four seasonal samplings undertaken between 2009 and 2010 at five sites were analyzed. Dichloromethane extracts were obtained under sonication and subjected to mutagenicity assays using Salmonella microsuspension. metal (Cd, Cr, Cu, Ni and Pb) contents were determined by atomic absorption spectrometry, while the quantification of PAHs was performed by gas chromatography-mass spectrometry. Goniopsis cruentata hemocytes were used to assess potential genotoxic damage (micronucleus assay). The absence of mutagenicity was observed for all samples using Salmonella typhimurium strains TA97, TA98, TA100 and TA102, in the absence and presence of an exogenous mammalian metabolizing system. Among the metals, Cd and Cu were detected in autumn at values exceeding the threshold effect level and below the probable effect level. Benzo[a] pyrene was detected at levels above the threshold at one site, where small effects could be observed in the biota. Significant differences in the micronucleated cells observed suggest DNA damage had been induced by the PAHs identified.

关键词： Sediments mutagenicity Goniopsis cruentata Genotoxicity Polycyclic Aromatic Hydrocarbons(PAHs) metals

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

mapping nighttime Pm2.5 from VIIRS DNB using a linear mixed effects model

Mapping nighttime PM2.5 from VIIRS DNB using a linear mixed ...

引用

第十三届全国气溶胶会议

作者： D.Fu X.Xia m.Duan X.Zhang X.Li J.Wang LAGEO Institute of Atmospheric PhysicsChinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences Collaborative Innovation Center on Forecast and Evaluation of meteorological Disasters Nanjing University of Information Science&Technology School of Atmospheric Sciences Plateau Atmosphere and Environment Key Laboratory of Sichuan ProvinceChengdu University of Information Technology National Satellite meteorological Center China Meteorological Administration Department of Chemical and Biochemical Engineering Center for Global and Regional Environmental Studiesand Informatics InitiativeThe University of Iowa

Estimation of particulate matter with aerodynamic diameter less than 2.5 μm(Pm) from daytime satellite aerosol products is widely reported in the literature, however, remote sensing nighttime Pm from space is very *** shows a distinct diurnal cycle and Pm concentration at 1:00 local standard time(LST) has a linear correlation coefficient(R) of 0.80 with daily-mean ***, estimation of nighttime Pm is required for fully understanding of temporal variation of Pm and its effects on air *** data from the Day/Night Band(DNB) of the Visible Infrared Imaging Radiometer Suite(VIIRS) and hourly Pm data at 35 stations in Beijing, a mixed effects model has been developed to estimate nighttime Pm from nighttime light radiance measurements based on the assumption that the DNB-Pm relationship is constant spatially but varies ***-validation showed that the model developed using all stations could predict Pm with mean determination coefficient(R) of 0.87± 0.12, 0.83±0.10, 0.87± 0.09, 0.83± 0.10 in spring, summer, autumn and *** analysis showed that the best model performance was achieved in urban stations with average crossvalidation R of *** rural stations, DNB light signal was likely contaminated by lunar illuminance that resulted in relatively poor estimation of *** fixed and random parameters of the mixed effects model in urban stations differed from those in suburban stations, which indicated that the assumption of the mixed effects model should be carefully evaluated when the method was used at a regional scale.

关键词： VIIRS/DNB the mixed effects model nighttime Pm 2.5

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

家兔超数排卵结果报道

引用

广西农业大学学报 1994年第1期13卷 93-98页

作者：谭世俭李雪峰谭丽玲 A.m.AbuBaker 广西农业大学动物繁殖研究室华南师范大学激光生命科学所

在１９９１～１９９３年间，应用国产和进口的促卵泡素（ＦＳＨ）及国产的孕马血清促性腺激素（ＰＭＳＧ）和人绒毛膜促性腺激素（ＨＣＧ），对１３６只母兔进行超数排卵处理试验。结果显示，国产的高活性ＦＳＨ对母兔有良好的超排作用... 详细信息

在１９９１～１９９３年间，应用国产和进口的促卵泡素（ＦＳＨ）及国产的孕马血清促性腺激素（ＰＭＳＧ）和人绒毛膜促性腺激素（ＨＣＧ），对１３６只母兔进行超数排卵处理试验。结果显示，国产的高活性ＦＳＨ对母兔有良好的超排作用。试验母兔中有８５％表现超排效应，平均每只母兔可回收到３１．１个卵，几乎相当于对照组（自然发情组，８．５个／只）的４倍。母兔对超排的反应表现出明显的季节性，春季时的处理效果极显著地优于秋季。其中ＦＳＨ组在春、秋季的回收卵数分别为３５．０个／只与１１．９个／只，差异十分显著（Ｐ＜０．００１）；ＰＭＳＧ组也表现类似效果。另外，注射ＨＣＧ后不同回收时间对卵回收数的影响也很大。在注射了ＨＣＧ１３．５ｈ后卵母细胞的回收数非常显著地比１３．５ｈ前高，两者几乎相差１倍（３６．０：１８．３）。同时，母兔左、右侧卵巢排卵数也表现出明显差异，不论是自然发情或人工超排，母兔右侧卵巢的排卵数均显著地高于左侧卵巢。

关键词：兔促性腺激素超数排卵排卵数

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

Tillage, Crop Rotation, and Cultural Practice Effects on Dryland Soil Carbon Fractions

引用

Open Journal of Soil Science 2012年第3期2卷 242-255页

作者： Upendra m. Sainju Andrew W. Lenssen Thecan Caesar-TonThat Jalal D. Jabro Robert T. Lartey Robert G. Evans Brett L. Allen Agronomy Deaprtment Iowa State University Ames IA 50011 USA. U.S. Department of Agriculture Agricultural Research Service Northern Plains Agricultural Research Laboratory 1500 North Central Avenue Sidney Montana 59270 USA

Information is needed on novel management practices to increase dryland C sequestration and soil quality in the northern Great Plains, USA. We evaluated the effects of tillage, crop rotation, and cultural practice on dryland crop biomass (stems and leaves) yield, surface residue, and soil C fractions at the 0-20 cm depth from 2004 to 2008 in a Williams loam in eastern montana, USA. Treatments were two tillage (no-tillage [NT] and conventional tillage [CT]), two crop rotations (continuous spring wheat [Triticum aestivum L.] [CW] and spring wheat-barley [Hordeum vulgaris L.] hay-corn [Zea mays L.]-pea [Pisum sativum L.] [W-B-C-P]), and two cultural practices (regular [conventional seed rates and plant spacing, conventional planting date, broadcast N fertilization, and reduced stubble height] and ecological [variable seed rates and plant spacing, delayed planting, banded N fertilization, and increased stubble height]). Carbon fractions were soil organic C (SOC), particulate organic C (POC), microbial biomass C (mBC), and potential C mineralization (PCm). Crop biomass was 24% to 39% greater in W-B-C-P than in CW in 2004 and 2005. Surface residue C was 36% greater in NT than in CT in the regular practice. At 5 - 20 cm, SOC was 14% greater in NT with W-B-C-P and the regular practice than in CT with CW and the ecological practice. In 2007, POC and PCm at 0 - 20 cm were 23 to 54% greater in NT with CW or the regular practice than in CT with CW or the ecological practice. Similarly, mBC at 10 - 20 cm was 70% greater with the regular than with the ecological practice in NT with CW. Surface residue, PCm, and mBC declined from autumn 2007 to spring 2008. No-tillage with the regular cultural practice increased surface residue and soil C storage and microbial biomass and activity compared to conventional tillage with the ecological practice. mineralization reduced surface residue and soil labile C fractions from autumn to spring.

关键词： Carbon Sequestration Dryland Soil Labile Carbon management Practices Residue Carbon

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

Cattle-Breeding Valley Plains and C4 Spontaneous Grasses in North Patagonia

引用

Journal of Environmental Science and Engineering(A) 2020年第6期9卷 266-272页

作者： m.Guadalupe Klich Universidad Nacional de Río Negro Escuela de Veterinaria y Producción AgroindustrialCIT-UNRN-CONICETChoele Choel 8360Argentina

The climate of North Patagonia (Argentina) is semiarid and the region periodically suffers severe droughts that may lastseveral years, decreasing forage offer and consequently cow livestock and productivity. In most of the cattle fields extensive grazing isusually continuous through the year-long. The absence of pasture rotational schemata affects rangeland health changing thecomposition of plants communities in detriment of the valuable species. When under a severe drought, the appreciated forageLeptochloa crinita (= Trichloris crinita) stopped reproduction and the population became scarce, a grazing schedule was designed in acattle farm to avoid foraging during spring and summer in a paddock located in the valley plains, where the species was *** L. crinita populations, the sympatric presence of the Poaceae Aristida mendocina, Distichlis spicata and Distichlis scoparia isexpected, each one in slightly different patches within the same area. The forage value differs between species but all of them are eatenby bovines. For ten years the plant communities were studied with the aims of determining the incidence of the patches on the paddockcarrying capacity in early autumn and estimating the contribution of the four C4 species to bovine diet by microhistology. Free ofgrazing during its growing period, L. crinite enhanced the area of its patches and the biomass production of its good quality forage andwas consumed preferently. A. mendocina is not prized by cattle but contributed to the diet at the end of the foraging period. Distichlisspp. is important component of the cows’ diet, especially in dry years. management actions to preserve a valuable species may haveside effects involving other community members.

关键词： Bovine diet C4 grasses patches management

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：