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Robert Kreuzig 《洁净——土壤、空气、水》2010,38(8):697-705
Veterinary medicines and biocides are frequently applied in animal houses of livestock husbandry. Due to these application patterns, they reach liquid manure. So far these substances are not transformed during manure storage, they enter soil by the application of manure as organic fertilizer. Therefore, biodegradability of veterinary medicines and biocides in manure is in the focus of regulatory procedures of environmental risk assessment. Since the representative and reproducible sampling of manures from high volume tanks is considered impossible due to high matrix variabilities, the reference manure concept was developed to utilize liquid bovine and pig manures for reproducible laboratory testing. Accordingly, excrement samples of cattle and pigs individually kept at experimental and conventional animal houses were taken. Tap water was added to matrix characterized excrements in order to prepare bovine and pig reference manures of 10 and 5% dry substance contents, respectively. Subsequently, the long‐term transformation of selected 14C‐labeled test substances was investigated under strictly anaerobic conditions. The application of different batches of bovine or pig reference manures indicated that extrapolation of transformation rates within the same animal species was possible. However, results cannot be transferred from bovine to pig manure because of substance specific interactions with the different manure matrices. The dependency of metabolic dynamics on different dry substance contents (2.5, 5, 10%) was additionally investigated in both manure matrices. These tests clearly showed that the dry substance content of the reference manure is one of the most relevant factors affecting the transformation of veterinary medicines and biocides. In contrast to highly variable tank manures, the reference manure concept allows for the exact adjustment of this parameter to guarantee reproducible laboratory testing. 相似文献
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在局地热平衡情况下,将物理量先用韦伯函数展开,然后去掉相应分量的滤波方 法,讨论了简单热带海气耦合模型中不同形式扰动的作用和贡献,结果表明,在热带海气耦合 系统中,大气准定常 Rossby波和海洋 Rossby波对于耦合系统贡献较大,它们决定着耦合系统 与耦合扰动的性质,而大气准定常Kelvin波和海洋Kelvin波对于耦合系统贡献相对较小. 相似文献
46.
采用包括耗散的射线跟踪方法,计算了在水平不均匀风场作用下,不同尺度重力波从对流层直至220km观测高度的传播,结果表明,垂直于重力波传播方向的风以及风剪切能够引起波射线的折射,从而导致重力波明显偏离初始传播方向.在强顺风场作用下,由于风场引起的捕获,大量重力波不能传播到观测高度.由于风场引起的多普勒频移,小周期的重力波在弱顺风条件下能够传播到观测高度.由于反射作用,强逆风场不支持周期低于约18min的较高频重力波的传播.而在弱逆风作用下,大部分中尺度范围重力波都能够传播到观测高度.本文统计了武汉电离层观象台的TID观测数据随热层风场的分布,统计结果与模拟结果符合较好. 相似文献
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VSP资料上下行波场发育丰富.本文在分析VSP直达波、上行反射波、下行反射波传播路径及其照明范围的基础上,指出了常规VSP波动方程偏移方法缺陷,进而通过修改波场延拓方式,提出了上下行反射波联合成像方法,并在高频近似下分析了该方法的成像原理.该方法不需要进行VSP上下行反射波场分离,能够同时对VSP资料中的一次反射波、自由表面多次波、层间多次波进行成像,比常规成像剖面具有更宽的成像范围和更好的成像效果.该方法能够对下行一次反射波进行成像,从而可以实现常规偏移方法难以处理的高陡倾角构造成像.模拟资料和实际资料处理证明了本文方法的正确性. 相似文献
48.
Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model 总被引:1,自引:0,他引:1
Current theories of F-layer storms are discussed using numerical simulations with the Upper Atmosphere Model, a global self-consistent, time dependent numerical model of the thermosphere-ionosphere-plasmasphere-magnetosphere system including electrodynamical coupling effects. A case study of a moderate geomagnetic storm at low solar activity during the northern winter solstice exemplifies the complex storm phenomena. The study focuses on positive ionospheric storm effects in relation to thermospheric disturbances in general and thermospheric composition changes in particular. It investigates the dynamical effects of both neutral meridional winds and electric fields caused by the disturbance dynamo effect. The penetration of short-time electric fields of magnetospheric origin during storm intensification phases is shown for the first time in this model study. Comparisons of the calculated thermospheric composition changes with satellite observations of AE-C and ESRO-4 during storm time show a good agreement. The empirical MSISE90 model, however, is less consistent with the simulations. It does not show the equatorward propagation of the disturbances and predicts that they have a gentler latitudinal gradient. Both theoretical and experimental data reveal that although the ratio of [O]/[N2] at high latitudes decreases significantly during the magnetic storm compared with the quiet time level, at mid to low latitudes it does not increase (at fixed altitudes) above the quiet reference level. Meanwhile, the ionospheric storm is positive there. We conclude that the positive phase of the ionospheric storm is mainly due to uplifting of ionospheric F2-region plasma at mid latitudes and its equatorward movement at low latitudes along geomagnetic field lines caused by large-scale neutral wind circulation and the passage of travelling atmospheric disturbances (TADs). The calculated zonal electric field disturbances also help to create the positive ionospheric disturbances both at middle and low latitudes. Minor contributions arise from the general density enhancement of all constituents during geomagnetic storms, which favours ion production processes above ion losses at fixed height under day-light conditions. 相似文献
49.
《Urban geography》2013,34(7):662-682
Complementary and alternative medical approaches such as chiropractic, massage, acupuncture, holistic, and naturopathic therapies act as complements to, and in some cases replacements for, conventional medical techniques. The growing acceptance of the benefits of "traditional" medicine in the Canadian province of Ontario continues to provide complementary and alternative medicine (CAM) practitioners with business opportunities, but to date little attention has been directed toward the spatial patterns exhibited by these operations. A province-wide database of 4,599 records, containing addresses and selected characteristics (e.g., sales, employment) of CAM offices, is utilized to describe the geographic pattern across Ontario. An additional database allows for the assessment of four intermediate-sized census metropolitan areas (CMAs) in Ontario (Kingston, Guelph, Thunder Bay, and Greater Sudbury), and it is determined (using a general nearest neighbor analysis and a nearest neighbor hierarchical clustering procedure) that CAM offices are significantly clustered in specific portions of each CMA. The results from a survey administered to CAM practitioners suggests that the benefits of urbanization economies are biasing location decisions within these CMAs, and that localization economies advantages appear to be influencing complementary and alternative healthcare specialists to share offices. 相似文献
50.
Richard B. Rood 《Pure and Applied Geophysics》1985,123(5):733-755
The concept of planetary wave breaking (McIntyre andPalmer, 1983; 1984) is critically reviewed. It is concluded that the wave breaking signature is not unique to any particular dynamic event in the stratosphere. Therefore, the classification of stratospheric transport events, such as wave breaking, groups fundamentally different events together. Better qualification of the wave breaking signature and a more solid theoretical basis of planetary wave breaking must be presented if the concept is to be of significant utility in describing stratospheric tracer transport. 相似文献