检索结果-南通市图书馆

Assessment of Ecotoxicity of Topsoils from a Wood Treatment Site

Pedosphere 2009年第2期19卷 143-155页

作者： M. MENcH c.BES UMR BIOGEcO INRA 1202 Ecology of Communities University of Bordeaux 1 Bt B8 RdC Estgate 002Avenue des Facults F-33405 Talence (France) UMR BIOGEcO INRA 1202 Ecology of CommunitiesUniversity of Bordeaux 1Bt B8 RdC Estgate 002 Avenue des Facults F-33405 Talence (France)

A series of 9 soil samples were taken at a timber treatment site in SW France where cu sulphate and chromated copper arsenate （ccA） have been used as wood preservatives （Sites P1 to P9） and one soil sample was collected at an adjacent site on the same soil type （Site P10）. copper was a major contaminant in all topsoils, varying from 65 （Soil P5） to 2600 mg cu kg^-1 （Soil P7）, exceeding background values for French sandy soils. As and cr did not accumulate in soil, except at Site P8 （52 mg As kg^-1 and 87 mg cr kg^-1） where ccA-treated posts were stacked. Soil ecotoxicity was assessed with bioassays using radish, lettuce, slug Arion rufus L., and earthworm Dendrobaena octaedra （Savigny）. There were significantly differences in lettuce germination rate, lettuce leaf yield, radish root and leaf yields, slug herbivory, and earthworm avoidance. An additional bioassay showed higher negative impacts on bean shoot and root yields, Rhizobium nodule counts on Bean roots, and guaiacol peroxidase activity in primary Bean leaves for soil from Site PT, with and without fertilisation, than for soil from Site P10, despite both soils having a similar value for computed free ion cu2＋ activity in the soil solution （pcu^2＋）. Beans grown in soil from Site P7 that had been fertilised showed elevated foliar cu content and phytotoxic symptoms. Soils from Sites P7 （treatment plant） and P6 （storage of treated utility poles） had the highest ecotoxicity, whereas soil from Site P10 （high organic matter content and cation exchange capacity） had the lowest. Except at Site P10, the soil factor pcu^2＋ computed with soil pH and total soil cu could be used to predict soil ecotoxicity.

关键词： contaminated soil copper ecotoxicity test invertebrate plant.

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

Growth response of three plantation species of the tropics exposed to elevated cO_2 levels

引用

Journal of Forestry Research 2013年第3期24卷 449-456页

作者： Rekha R. Warrier c. Buvaneswaran P. Priyadharshini R.S.c. Jayaraj Institute of Forest Genetics and Tree Breeding Forest CampusR. S. Puram Coimbatore 641002 India

The response of forest trees, the largest carbon sinks on the earth, to continuing rise in atmospheric carbon levels is unknown. Re- ports state that increasing levels of atmospheric cO2 will stimulate pho- tosynthesis and productivity in most ecosystems. However, the duration and magnitude of this stimulation, particularly in the tropics, remains a question. To investigate the effects of cO2 fertilization on plant growth, seedlings of three common plantation species, casuarina equisetifolia, Ailanthus excelsa and Tectona grandis were grown in closed chambers enriched with cO2. After 180 days of treatment, morphological traits of seedling height, biomass of root and shoot and root-shoot allometric co-efficient were measured. The activity of carbonic anhydrase and con- tents of chlorophylls, total carbohydrates and soluble proteins were de- termined. In Tectona grandis, significant effects of cO2 supply were found on chlorophylls, root-shoot allometric ratio and seedling quality index. Ailanthus excelsa showed significant effect on only the shoot characteristics on exposure to elevated cO2 but the root characteristics and concentrations of chlorophylls were not significantly different. ca- suarina equisetifolia also showed significant effects on exposure to ele- vated cO2 in terms of shoot characteristics and concentrations of chlo- rophylls. Total sugars, the major photosynthates, did not show any sig- nificant variation to elevated cO2 in any of the three species. carbonic anhydrase, the key enzyme responsible for transfer of cO2 into the tis- sues significantly increased in all three species. Overall, all the variables responded to elevated cO2, reflecting the positive effects of one parame- ter of climate change conditions on seedling quality. A positive response of these three plantation species to elevated cO2 content is a good indi- cation for their future existence in potentially changed climatic eonditions.

关键词： Plantation Elevated cO2 Tropical trees India carbonicanhydrase

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

Soil Temperature Dependent Growth of cotton Seedlings Before Emergence

引用

Pedosphere 2008年第1期18卷 54-59页

作者： G.NABI c.E.MULLINS Land Resources Research Program National Agricultural Research CentrePark RoadIslamabad45500 (Pakistan) Department of Plant and Soil Science Cruickshank BuildingUniversity of AberdeenAB24 3UU (UK)

Soil temperature is an important variable governing plant growth and development. Studies were conducted under laboratory conditions to determine the effect of soil temperature on root and shoot growth of cotton during emergence. cotton seedlings were grown for 192 h at 20, 32 and 38℃ in soil packed in 300 mm long and 50 mm diameter cylinders. The data indicated that the longest roots （173 ram） as well as shoots （152 mm） were recorded at 32℃ followed by 20 （130 mm root and 82 mm shoot） and 38℃ （86 mm root and 50 mm shoot）. roots grown at 20 and 38 ℃ were 20% and 50% shorter, respectively, than those grown at 32℃ after 192 h. roots and shoots exhibited the lowest length and dry biomass at 38 ℃. Shoot lengths grown at 20 （74 mm） and 38℃（51 mm） were 44% and 61% shorter than those grown at 32℃（131 mm） after 180 h growth period, respectively. Growth at all three temperatures followed a similar pattern. Initially there was a linear growth phase followed by the reduction or cessation of growth. Time to cessation of growth varied with temperature and decreased faster at higher temperatures. Sowing of cotton should be accomplished before seedbed reaches a soil temperature （≥ 38 ℃） detrimental for emergence. Further, the seedbeds should be capable of providing sufficient moisture and essential nutrients for emerging seedling before its seed reserves are exhausted to enhance seedling establishment in soil.

关键词： linear growth root/shoot elongation soil temperature

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

A Generic Model to Estimate Wheat LAI over Growing Season Regardless of the Soil-Type Background

引用

Plant Phenomics 2023年第2期5卷 333-352页

作者： Qiaomin chen Bangyou Zheng Karine chenu Scott c.chapman School of Agriculture and Food Sciences The University of QueenslandSt LuciaQLDAustralia Agriculture and Food CSIROQueensland Bioscience PrecinctSt LuciaQLDAustralia The University of Queensland Queensland Alliance for Agriculture and Food InnovationToowoombaQLDAustralia

It is valuable to develop a generic model that can accurately estimate the leaf area index(LAI)of wheat from unmanned aerial vehicle-based multispectral data for diverse soil backgrounds without any ground *** achieve this objective,2 strategies were investigated to improve our existing random forest regression(RFR)model,which was trained with simulations from a radiative transfer model(PROSAIL).The 2 strategies consisted of(a)broadening the reflectance domain of soil background to generate training data and(b)finding an appropriate set of indicators(band reflectance and/or vegetation indices)as inputs of the RFR *** RFR models were tested in diverse soils representing varying soil types in *** analysis indicated that adopting both strategies resulted in a generic model that can provide accurate estimation for wheat LAI and is resistant to changes in soil *** validation on 2 years of field trials,this model achieved high prediction accuracy for LAI over the entire crop cycle(LAI up to 7 m^(2)m^(−2))(root mean square error(RMSE):0.23 to 0.89 m^(2)m^(−2)),including for sparse canopy(LAI less than 0.3 m^(2)m^(−2))grown on different soil types(RMSE:0.02 to 0.25 m^(2)m^(−2)).The model reliably captured the seasonal pattern of LAI dynamics for different treatments in terms of genotypes,plant densities,and water–nitrogen managements(correlation coefficient:0.82 to 0.98).With appropriate adaptations,this framework can be adjusted to any type of sensors to estimate various traits for various species(including but not limited to LAI of wheat)in associated disciplines,e.g.,crop breeding,precision agriculture,etc.

关键词： soil Wheat breeding

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 Ice on Soil Elemental characterization via Portable X-Ray Fluorescence Spectrometry

引用

Pedosphere 2014年第1期24卷 1-12页

作者： D.c.WEINDORF N.BAKR Y.ZHU A.McWHIRT c.L.PING G.MIcHAELSON c.NELSON K.SHOOK S.NUSS Texas Tech University Department of Plant and Soil Sciences Louisiana State University Agricultural center University of Alaska Fairbanks Palmer Research Center

Field portable X-ray fluorescence （PXRF） spectrometry has become an increasingly popular technique for in-situ elemental characterization of soils. The technique is fast, portable, and accurate, requiring minimal sample preparation and no consumables. However, soil moisture 〉 20% has been known to cause fluorescence denudation and error in elemental reporting and few studies have evaluated the presence of soil moisture in solid form as ice. Gelisols （USDA Soil Taxonomy）, permafrost-affected soils, cover a large amount of the land surface in the northern and southern hemispheres. Thus, the applicability of PXRF in those areas requires further investigation. PXRF was used to scan the elemental composition （Ba, ca, cr, Fe, K, Mn, Pb, Rb, Sr, Ti, Zn, and Zr） of 13 pedons in central and northern Alaska, USA. Four types of scans were completed： 1） in-situ frozen soil, 2） re-frozen soil in the laboratory, 3） melted soil/water mixture in the laboratory, and 4） moisture-corrected soil. All were then compared to oven dry soil scans. Results showed that the majority of PXRF readings from in-situ, re-frozen, and melted samples were significantly underestimated, compared to the readings on oven dry samples, owing to the interference expected by moisture. However, when the moisture contents were divided into 〉 40% and 〈 40〈 groups, the PXRF readings under different scanning conditions performed better in the group with 〈 40% moisture contents. Most elements of the scans on the melted samples with 〈 40% moisture contents acceptably compared to those of the dry samples, with R2 values ranging from 0.446 （Mn） to 0.930 （St）. However, underestimation of the melted samples was still quite apparent. Moisture-corrected sample PXRF readings provided the best correlation to those of the dry, ground samples as indicated by higher R2 values, lower root mean square errors （RMSEs）, and slopes closer to 1 in linear regression equations. However, the in-situ （frozen） sample scans did not differ

关键词： Gelisols moisture permafrost proximal sensing regression

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

A vector autoregression weather model for electricity supply and demand modeling

引用

Journal of Modern Power Systems and clean Energy 2018年第4期6卷 763-776页

作者： Yixian LIU Matthew c.ROBERTS Ramteen SIOSHANSI Department of Integrated Systems Engineering The Ohio State University Department of Agricultural Environmental and Development Economics The Ohio State University

Weather forecasting is crucial to both the demand and supply sides of electricity systems. Temperature has a great effect on the demand side. Moreover, solar and wind are very promising renewable energy sources and are, thus, important on the supply side. In this paper, a large vector autoregression(VAR) model is built to forecast three important weather variables for 61 cities around the United States. The three variables at all locations are modeled as response variables. Lag terms are used to capture the relationship between observations in adjacent periods and daily and annual seasonality are modeled to consider the correlation between the same periods in adjacent days and years. We estimate the VAR model with16 years of hourly historical data and use two additional years of data for out-of-sample validation. Forecasts of up to six-hours-ahead are generated with good forecasting performance based on mean absolute error, root mean square error, relative root mean square error, and skill scores. Our VAR model gives forecasts with skill scoresthat are more than double the skill scores of other forecasting models in the literature. Our model also provides forecasts that outperform persistence forecasts by between6% and 80% in terms of mean absolute error. Our results show that the proposed time series approach is appropriate for very short-term forecasting of hourly solar radiation,temperature, and wind speed.

关键词： Forecasting Solar irradiance Wind speed Temperature Vector autoregression Skill scores

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

Long-distance ABA transport can mediate distal tissue responses by affecting local ABA concentrations

引用

Journal of Integrative Plant Biology 2018年第1期60卷 16-33页

作者： Wenrao Li carlos de Ollas Ian c Dodd college of Life Sciences Henan University Kaifeng 475004 China Plant & crop Sciences Lancaster Environment Center Lancaster University Lancaster LAI 4YQ United Kingdom

Environmental stresses that perturb plant Hwater relations influence abscisic acid(ABA) concentrations, but it is unclear whether long-distance ABA transport contributes to changes in local ABA levels. To determine the physiological relevance of ABA transport, we made reciprocal-and self-grafts of ABA-deficient flacca mutant and wild-type(WT) tomato plants, in which low phosphorus(P) conditions decreased ABA concentrations while salinity increased ABA concentrations. Whereas foliar ABA concentrations in the WT scions were rootstock independent under control conditions, salinity resulted in long-distance transport of ABA: flacca scions had approximately twice as much ABA when grafted on WT rootstocks compared to flacca rootstocks. root ABA concentrations were scion dependent: both WT and flacca rootstocks had less ABA with the flacca mutant scion than with the WT scion under control conditions. In WT scions, whereas rootstock genotype had limited effects on stomatal conductance under control conditions, a flacca rootstock decreased leaf area of stressed plants, presumably due to attenuated root-to-shoot ABA transport. In flacca scions, a WT rootstock decreased stomatal conductance but increased leaf area of stressed plants, likely due to enhanced root-to-shoot ABA transport. Thus, long-distance ABA transport can affect responses in distal tissues by changing local ABA concentrations.

关键词： ABA Long-distance ABA transport can mediate distal tissue responses by affecting local ABA concentrations Figure

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 kilosecond variability of X-ray sources in nearby galaxies

引用

Research in Astronomy and Astrophysics 2013年第12期13卷 1445-1454页

作者： Soma Mandal Ranjeev Misra Gulab c.Dewangan Department of Physics Taki Government College Inter-University centre for Astronomy and Astrophysics

chandra observations of 17 nearby galaxies were analyzed and 166 bright sources with X-ray counts 〉 100 were chosen for temporal analysis. Fractional root mean square （rms） variability amplitudes were estimated for light curves, binned at 4 kilosecond （ks）, with length 〈 40 ks. While there are nine ultra-luminous X- ray sources （ULXs） with unabsorbed luminosity （in the 0.3-8.0 keV band） L 〉 1039 erg s-1 in the sample for which the fractional rms variability is constrained to be 〈 10%, only two of them show variability. One of the variable ULXs exhibits a secular transition and has an ultra-soft spectrum with temperature - 0.3 keV while the other is a rapidly varying source in NGc 0628, which has previously been com- pared to the Galactic microquasar GRS 1915＋105. These results seem to indicate that ULXs are typically not highly variable on ks timescales, except for some ultra-soft ones. Among the relatively low luminosity sources （L - 10^38 erg s-1）, we find five of them to be variable. Apart from an earlier known source in NGc 1569, we identify a source in NGc 2403 that exhibits persistent high amplitude fluctuations. In general, the variability of the sources does not seem to be correlated with hardness, which indicates that they may not be due to variations in any absorbing material, but instead could reflect instabilities in the inner accretion disk.

关键词： galaxies: general --X-rays: binaries

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

Data-driven Static Equivalence with Physics-informed Koopman Operators

引用

cSEE Journal of Power and Energy Systems 2024年第1期10卷 432-438页

作者： Wei Lin changhong Zhao Maosheng Gao c.Y.chung Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong Kong SARChina Department of Information Engineering The Chinese University of Hong KongHong Kong SARChina School of Electrical Engineering Chongqing UniversityChongqing 400044China

With deployment of measurement units,fitting static equivalent models of distribution networks(DNs)by linear regression has been recognized as an effective method in power flow analysis of a transmission *** volatility of measurements caused by variable distributed renewable energy sources makes it more difficult to accurately fit such equivalent *** tackle this challenge,this letter proposes a novel data-driven method to improve equivalency accuracy of DNs with distributed energy *** letter provides a new perspective that an equivalent model can be regarded as a mapping from internal conditions and border voltages to border power *** mapping can be established through 1)Koopman operator theory,and 2)physical features of power flow equations at the root node of a *** of the proposed method is demonstrated on the IEEE 33-bus and IEEE 136-bus test systems connected to a 661-bus utility system.

关键词： Data-driven distribution network Koopman operator theory static equivalent model

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

connecting supplier and DoD blockchains for transparent part tracking

引用

Blockchain(Research and Applications) 2021年第3期2卷 17-30页

作者： Francis Asuncion Adam Brinckman Dwayne cole Jeffrey curtis Matt Davis Timothy Dunlevy calvin Farmer Andrew Harrison Daniel P.Johnson Joshua Joyce c.ris Klubertanz Jonathan Lane John Martin Jarek Nabrzyski Joel Neidig Deysi Olivares Gregory Robinson Gabriel Rodriguez c.ris root Karen Rowand Al Salour Jeff Score David Scott Ian Taylor chandler Thompson Huy Truong Xiqun Wang Dale Warren NAVAIR USA SIMBA chain PlymouthIN46563USA center for Research computing University of Notre DameNotre DameIN46556USA Indiana Technology and Manufacturing companies(ITAMcO) PlymouthIN46563USA Boeing company USA Naval Systems Inc.USA

Blockchains have been around for more than ten years,and since 2015,a plethora of systems have been launched to target more flexible use *** recently,several enterprise blockchain systems,such as consensys Quorum and Hyperledger Fabric,have been launched to make blockchain simpler to apply in complex organizational *** this paper,we identify a specific Department of Defense use case,extrapolate requirements,and perform a thorough assessment of the different layers of the blockchain stack to identify the existing state of the art and undertake a gap analysis of the technology for this *** describe a platform that meets many of these challenges and show how we architected,designed,and implemented a solution for this use case for deployment at *** solution connects transactions from two separate blockchain systems,consensys Quorum and Hyperledger Fabric,by using a graph-based approach that preserves privacy while enabling full transparency across the military and supplier networks.

关键词： Blockchain Smart contracts Supply chain Department of defense(DoD) GraphQL Enterprise blockchain systems

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：