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1.
The analysis in this paper is directed at comparing the relative effectiveness of meeting the objectives outlined in the recently passed Clean Air Act Amendments of 1990 through taxation and through regulation. The analytical vehicle used in the analysis consists of a computable general equilibrium model composed of 12 producing sectors, 13 consuming sectors, 6 household categories classified by income, a foreign sector and a government. We find first that, irrespective of what type of strategy is followed, both output and consumption decline. Hence, there is an identifiable and quantifiable tradeoff between economic activity (economic growth) and the quality of the environment. Beyond this, the aggregate loss in production and economic welfare (measured by consumption expenditures and utility) is less under a policy which stresses reliance on alternative fuels than through one that requires the installation of pollution abatement devices. 相似文献
2.
Development of an ELISA for the detection of the residues of the fungicide iprovalicarb 总被引：3，自引：0，他引：3
Lee JK Park SH Lee EY Kim YJ Kyung KS 《Journal of agricultural and food chemistry》2004,52(22):6680-6686
A competitive indirect enzyme-linked immunosorbent assay was developed for the fungicide iprovalicarb, using a polyclonal antibody produced against a hapten conjugated through the carboxyl group on the benzene ring to keyhole limpet hemocyanin. Under an optimized condition using a heterologous format, an IC(50) of 3.51 ng/mL and the lowest detection limit of 0.065 ng/mL were obtained. When the isopropoxy group was removed from the iprovalicarb structure for the synthesis of a hapten, the resulting hapten was not successful as an immunogen, indicating that the isopropyl moiety was an important epitope, as evidenced by the cross-reactivities of some structurally related compounds. When applied to the real crop and water samples, the recoveries were in the range of 80.52-144.70% (n = 4) and 72.11-100.43% (n = 4), respectively. Accordingly, this ELISA can be used as a useful method for monitoring iprovalicarb residues in crop and water samples. 相似文献
3.
跟踪学科前沿，引导学科发展——《农业工程学报》的发展探索 总被引：1，自引：1，他引：1
论述了《农业工程学报》跟踪农业工程学科发展的成功经验，详细分析了未来《农业工程学报》跟踪学科各个专业的报道方向。指出随着学科的发展及时调整学术期刊的报道方向是科技学术期刊的任务和职责，是使期刊保证及时反映相关学科的发展，保持在学科发展中应有的促进作用，在众多期刊的竞争中立于不败之地的保证。在充分分析中国学术期刊面临的形势和问题、机遇与挑战的基础上，提出了学术期刊如何规避不利因素等应对策略，为中国科技学术期刊的发展提供参考。 相似文献
4.
The role of diffusion in the kinetics of phosphate desorption: the relevance of the Elovich equation 总被引：4，自引：0，他引：4
Various kinetic expressions were tested with phosphate desorption data from four contrasting soils and found inadequate, but the data supported a model recently proposed by Aharoni and Suzin. This model assumes that chemisorption reactions are kinetically controlled by diffusion and integration of Pick's equation, under appropriate boundary conditions, results in an expression for the time dependence of adsorption or desorption, that can be approximated by a sequence of equations-parabolic, Elovich and exponential–at small, intermediate and large times, respectively. Thus, full or even partial conformation of data to such a sequence would suggest diffusion control of the rate determining step, a suggestion usually relying on a time relationship alone.
Since true rate constants could not be derived from the other expressions tested, calculation of physically meaningful activation energies was not possible. An approach to the calculation of activation energies at different stages of the process, based on the model of Aharoni and Suzin, and the difficulties encountered are also discussed. 相似文献
Since true rate constants could not be derived from the other expressions tested, calculation of physically meaningful activation energies was not possible. An approach to the calculation of activation energies at different stages of the process, based on the model of Aharoni and Suzin, and the difficulties encountered are also discussed. 相似文献
5.
Yu. G. Chendev A. L. Aleksandrovskii O. S. Khokhlova M. I. Dergacheva A. N. Petin A. N. Golotvin V. A. Sarapulkin G. L. Zemtsov S. V. Uvarkin 《Eurasian Soil Science》2017,50(1):1-13
The Late Holocene stage of forest pedogenesis has been studied on the interfluves along river valleys in the forest-steppe zone of the Central Russian Upland. The development of gray forest soils from the former chernozems as a result of the Late Holocene advance of forest vegetation over steppes is discussed. It is argued that the climatic conditions of the Subatlantic period were unstable, so that multiple alternation of forest and steppe vegetation communities took place. This specified a complex character of soil evolution upon contrasting substitution of forest pedogenesis for steppe pedogenesis. On the interfluves near the natural drainage network (balkas, ravines, and steep slopes of river valleys), the climate-driven dynamics of forest and steppe vegetation with corresponding changes in the character of pedogenesis could take place during the entire Holocene, which is reflected in a lower thickness of humus profiles and deeper leaching of carbonates from chernozems of the Early Iron Age in comparison with their analogues formed under steppe cenoses in central parts of the interfluves. Two variants of the evolution of gray forest soils can be suggested: the pulsating evolution typical of balkas and interfluves near river valleys and the continuous progressive evolution typical of automorphic (plakor) positions in central parts of the interfluves. 相似文献
6.
7.
In the surface 5 cm of a clay soil in 2 successive years the microbial biomass, as measured by a fumigation-respiration technique, was constant. The biomasses in two clay soils were approximately ten times greater than that in a silt loam. When straw from a preceding crop was chopped and left on the soil surface the biomass after 8 months was greater by a factor of two than that in soil where the straw had been burnt. Where soil had been kept in grass for 9 yr, the biomass was greater by a factor of three than that in soil of the same kind that had been in arable cultivation for the previous 4 yr. As the fumigation-respiration technique measured only the microbial and microfaunal contribution to the biomass, the total biomass can only be assessed by measuring the root contribution separately; when this was done the total biomass in the grassland was found to be greater by a factor of about six. 相似文献
8.
物联网是一个集信息通信、数据交换、传感器技术与软件工程于一体的综合性产业,探讨和分析了物联网的结构体系与发展中遇到的安全问题。 相似文献
9.
The anisotropy of the soil pores in texturally differentiated soils is an important soil-genetic index. The morphological
study of thin soil sections with vertical and horizontal orientation showed that the pore space of a texturally differentiated
light gray forest soil at the aggregate level of organization has isotropic, anisotropic, and partially anisotropic structures
in the different horizons. In the horizons with a platy structure, the anisotropy of the pore space is largely determined
by the anisometry of the structural units. In the horizons with a massive structure not separated into aggregates, the anisotropic
indices can be related to the structural features of the recent and relic biogenic pores. To reveal the total anisotropy of
the soil pore space, the most informative and genetically determined indices should be studied: the shape, area, and orientation
of the pores. In the soil studied, the variation of the pore sizes in the vertical thin sections was higher than in the horizontal
thin sections, which agreed with the concept of the anisotropy of the entire soil profile. The fixed vertical and horizontal
orientation of the soil thin sections allowed the obtained results to be integrated into the full-profile anisotropy of the
soil properties. The vertical thin sections were found to be of greater information value for the profile-genetic analysis
of the structure and variability of the soil pore space than their horizontal analogues. 相似文献
10.
在AquaCrop作物模型数据库组建的基础上,应用该模型对东北春小麦冠层生长进行模拟。结果表明,除2010年呼玛地区模拟值低于实测值外,其余年份和地点的模拟值均高于实测值,IoA在0.726～0.995之间,模拟值与实测值的一致性较为理想;AquaCrop模型能较好反映正常年份下春麦生育活动,模型模拟情况与各地观测到的冠层发育情况较为一致。但对极端气候下的春麦冠层发育的模拟效果较为一般。在以后的研究中,需进一步对气象参数做出修正,以更好地应用于小麦的生产和预测。 相似文献
11.
饮用水氯消毒及余氯控制技术展望 总被引：1，自引：0，他引：1
液氯作为一种消毒剂已有上百年历史,随着社会的发展,人们对健康意识的加强,氯消毒所引发的副作用越来越引起人们的重视。通过介绍液氯消毒原理,阐述余氯的几种基本测定方法及余氯在工艺上的控制和脱氯技术现状及发展方向。 相似文献
12.
The soil cover patterns in the subtaiga landscapes on the northern spurs of the Tsagan-Daban Ridge in the Selenga Mountains
have been studied. Gray-humus lithozems and bedrock outcrops are typical of the steep south-facing slopes under herbaceous
pine forests. Soddy iron-illuvial podburs are formed under forest vegetation on gentle slopes of northern and western aspects
with a thick mantle of loose colluvial deposits. Dark-humus metamorphic soils occur on the slopes of western and northwestern
aspects below 700 m a.s.l. under secondary forb-grassy communities that replaced the initial herbaceous pine forests. Windblown
hollows (yardangs) are occupied by humus psammozems under steppe pine forests. The morphological and physicochemical characteristics
of these soils are discussed in the paper. 相似文献
13.
The genesis and spatial differentiation of the silty sands and loams deposited during the Late Valdai glaciation have been studied in the central part of the Russian Plain within the Mologa-Sheksna Lowland and on terraced slopes of the Ovinishchensk Upland (Yaroslavl oblast). The stratigraphy of these sediments on different elements of the local topography and data on their particle-size distribution suggest that they belong to the same paragenetic group. Some differences in the particle-size distribution can be explained by the specificity of sedimentation in periglacial lakes found at different geomorphic levels (from 102 to 180 m a.s.l.) during the Ostashkov phase of the Valdai glaciation. For the first time, statistically significant differences in the properties of Holocene soils developed at different hypsometric levels have been revealed. The degree of textural differentiation of the soils developed from silty loams increases with an increase in the absolute height of the surface. The analysis of factual materials makes it possible to suggest that a system of impounded lakes existed in this area during the Ostashkov (maximum) phase of the Valdai cryochron; the water level in these lakes reached a maximum height of 180 m a.s.l. 相似文献
14.
Determining the bioavailability of contaminants and assessing the quality of sediments 总被引：1，自引：1，他引：0
Stephen AC Marklevitz Elizabete Almeida Joanna Flemming Jocelyne Hellou 《Journal of Soils and Sediments》2008,8(2):86-91
Background, Aims and Scope Our study determined the role of light, aeration, grain size, amount of sediments and of water, density of animals and presence
of additional food on the movement of Ilyanassa obsoleta. Spiked relative to reference sediments were also tested for avoidance or preference by the mud snails. Our goal was to develop
exposure conditions to be used in future assessment studies of the environmental quality of sediments inhabited by mud snails.
The behavioural response of the snails towards different concentrations of contaminated Halifax Harbour sediments placed in
one half of a tank relative to reference sediments in the other half is examined in Part 2 and a chemical link investigated.
Methods Animals were exposed in 7 L aquaria at 12°C to their native sediments placed in one or two halves of a tank and the effect
due to the presence of a light source, air bubbles, sediment grain size, added algae examined relative to the snails’ behaviour.
Preference or avoidance of one half of a tank relative to the second half, the immersed or dry glass surface represented the
various media to be chosen by snails. After choosing the optimum set up, exposures were performed in triplicate, under slightly
differing initial placement of the snails to compare means and variability in the results. Three specific biogenic chemicals,
cholesterol, coprostanol and a fatty acid methyl ester (FAME) were spiked at 0.002, 0.01, 0.05, 0.25 and 1.2 mg/g, dry weight
of sediment. A hexane, dichloromethane and methanol extract of harbour sediment were also spiked in reference sediments. In
all cases, the location of the snails was recorded over a period extending up to 96 hrs.
Results Twenty snails exposed during a 72 hrs period in commercial 7 L tanks containing 50 g of sediments (wet weight) in the bottom
half of a tank filled half way with seawater represented the chosen conditions to test the avoidance/preference behaviour
of snails for part of a tank. The presence of additional food on sediments attracted snails within 24 hrs of exposure.
Discussion A general lack of preference was indicated in exposures to three biologically derived compounds spiked in reference sediments,
i.e. a C-18 FAME, cholesterol and coprostanol. The repelling properties of a harbour sediment extract pointed to a role for
non polar chemicals.
Conclusions It is proposed that behaviour reflects a balance between the repelling effects of contaminants and the attractive value of
food. The present study provides a robust green assessment tool that is easy to set up to assess the quality of sediments.
Recommendations and Perspectives The interpretation of field observations regarding the abundance of animals during environmental assessments must consider
both nutritional and toxicological causes. Additional laboratory exposures are needed to determine which chemicals play a
role in the field. 相似文献
15.
Studies on the structure of the soil cover (SSC) on three sites under different environmental conditions showed that the traditional combination of SSC, the characteristics of soil and landforms indicate the structure of the soil at the level of elementary soil areas (ESAs) virtually independently from the features of the area under study. The waterlogging of the black soil is of a pronounced cyclical character; seasonal signs and periodic hydromorphic features are not retained in the SSC such that a conclusion about the transformation of ordinary black soil, for example, in meadow black soils, could be drawn, or the manifestation of this process in a variety of SSCs that differ in ecological features and landscape use of the Kamennaya steppe could be found. 相似文献
16.
N. V. Oreshnikova P. V. Krasilnikov S. A. Shoba 《Moscow University Soil Science Bulletin》2012,67(4):152-158
This paper studies marsh soils on the Karelian shore of the White Sea. The soil cover has been found to differ on shores of the open, closed, and transitional types. The open shores have mainly marsh primitive and soddy soils. In bays, there are marsh soddy gley and dredged peat gley soils, and the transitional shores have marsh peaty soils. All soils have poorly developed profiles, and their reaction is close to neutral. Organic and organic-mineral layers form depending on the position of a soil above sea level: a sod layer forms in uplands, and peaty and mud layers form in depressions, which are regularly flooded and have a high groundwater level. 相似文献
17.
P.W. van der Poel 《CATENA》1976,3(2):203-214
The measurement of growth indices of the beech (Fagus sylvativa) and of environmental conditions at 59 random sampling points were made in two areas of woodland in the Gutland region of Luxemburg (Grengewald and Warschent). Statistical analysis revealed that the main factor responsible for the growth of the beech is the parent material. Beech trees on sandstone are growing significantly better than those on marl. Moreover on sandstone, the beech trees are lowest on places having a thin A1 horizon and/or a high humus content of the A1 horizon and/or a southwest exposure. 相似文献
18.
19.
Moody John A. Sullivan John F. Taylor Howard E. 《Water, air, and soil pollution》2000,117(1-4):329-351
Concentrations of pollutants stored in the surficial bed sediments in the navigation pools of the Upper Mississippi River showed a general decrease after the record flood of 1993. Percent clay and total organic carbon in the surficial sediments decreased as a result of an increase in the proportion of coarser sediment. Decreases in pollutant concentration may have been a result of the dilution by coarser and relatively less polluted sediment that was mobilized and transported into the Upper Mississippi River from its tributaries or from mainstem locations upstream but outside of the sampling area. 相似文献
20.
《Communications in Soil Science and Plant Analysis》2012,43(1-2):377-386
Engrafted cuttings of the variety Rkaciteli on stocks B?×?R Cober 5BB and R?×?R 101-14, having endured open and covered stratification on different substrates, were planted in a polyethylene glasshouse on four artificial substrates after the postplanting preparation. The complex effect of the stock variety was examined, as well as the effects of the stratification methods and the substrates on the yield of engrafted vines. The characteristics of the regeneration of the engrafted cuttings during the stratification were established. The optimal substrates for stratification of the transplants and the growing of engrafted vines in glasshouses were defined. 相似文献