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271.
进入新世纪,作为信息载体的应用写作越来越受到社会重视,然而目前高职院校中的应用写作教学现状却与这种重视不相适应。为此,本文试就目前高职教学中如何改革应用写作教学方法的问题,从“应用写作课与相关课程互动”、“写作理论和写作实践互动”、“应用写作文种之间互动”、“促使教学主体进行互动”四个方面提出了看法,以期对高职应用写作教学改革有所裨益。 相似文献
272.
Ronald Parker J.G. Arnold Michael Barrett Lawrence Burns Lee Carrubba S.L. Neitsch N.J. Snyder R. Srinivasan 《Journal of the American Water Resources Association》2007,43(6):1424-1443
Abstract: The U.S. Environmental Protection Agency (USEPA) Office of Pesticide Programs (OPP) has completed an evaluation of three watershed‐scale simulation models for potential use in Food Quality Protection Act pesticide drinking water exposure assessments. The evaluation may also guide OPP in identifying computer simulation tools that can be used in performing aquatic ecological exposure assessments. Models selected for evaluation were the Soil Water Assessment Tool (SWAT), the Nonpoint Source Model (NPSM), a modified version of the Hydrologic Simulation Program‐Fortran (HSPF), and the Pesticide Root Zone Model‐Riverine Water Quality (PRZM‐RIVWQ) model. Simulated concentrations of the pesticides atrazine, metolachlor, and trifluralin in surface water were compared with field data monitored in the Sugar Creek watershed of Indiana’s White River basin by the National Water Quality Assessment (NAWQA) program. The evaluation not only provided USEPA with experience in using watershed models for estimating pesticide concentration in flowing water but also led to the development of improved statistical techniques for assessing model accuracy. Further, it demonstrated the difficulty of representing spatially and temporally variable soil, weather, and pesticide applications with relatively infrequent, spatially fixed, point estimates. It also demonstrated the value of using monitoring and modeling as mutually supporting tools and pointed to the need to design monitoring programs that support modeling. 相似文献
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The study was conducted to assess the potential of Norwegian agricultural ecosystems to sequester carbon (C) based on the data from some long-term agronomic and land use experiments. The total emission of CO2 in Norway in 1998 was 41.4 million metric ton (MMT), of which agriculture contributed only 0.157 MMT, or <0.4% of the total emissions. With regards to methane (CH4) and nitrous oxide (N2O) gases, however, agricultural activities contributed 32.5% and 51.3% of their respective emissions in Norway. The soil organic carbon (SOC) losses associated with accelerated soil erosion in Norway are estimated at 0.475 MMTC yr–1. Land use changes and soil/crop management practices with potential for SOC sequestration include conservation tillage methods, judicious use of fertilizers and manures, use of crop residues, diverse crop rotations, and erosion control measures. The potential for SOC sequestration is 0.146 MMTC yr–1 for adopting conservation tillage, 0.011–0.035 MMTC yr–1 for crop residue management, 0.026 MMTC yr–1 for judicious use of mineral fertilizer, 0.016–0.135 MMTC yr–1 for manure application, and 0.036 MMTC yr–1 for adopting crop rotations. The overall potential of these practices for SOC sequestration ranges from 0.591 to 1.022 MMTC yr–1 with an average value of 0.806 MMTC yr–1. Of the total potential, 59% is due to adoption of erosion control measures, 5.8% to restoration of peat lands, 21% to conversion to conservation tillage and residue management, and 14% to adoption of improved cropping systems. Enhancing SOC sequestration and improving soil quality, through adoption of judicious land use and improved system of soil and crop management, are prudent strategies for sustainable management of soil, water and environment resources.Readers should send their comments on this paper to:
bhaskarn ath@aol.com within 3 months of publication of this issue. 相似文献
275.
英语词汇对整个英语学习起着至关重要的作用.对于英语词汇的学习,大学生已经认识到了其重要性,但仍然存在各种各样的误区.为了提高学生的单词学习效率,教师应该采取科学方法来呈现英语词汇;借助英文电影、动画片、歌曲等激发学生的学习兴趣,以生动、形象、直观的方式进行英语词汇教学,给学生讲述成语和典故加深学生对英语词汇的印象和理解,采取灵活多样的教学形式进行英语词汇教学. 相似文献
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277.
人工加速老化测试--氙灯试验箱 总被引:3,自引:0,他引:3
讨论两种常见的、不同类型、测试条件一致的氙灯试验箱。详述了其不同的配置对光谱、辐照度控制、过滤器类型、潮湿、湿度控制、温度控制和校准等的影响。阐述了样品安置、设备的维护保养等实际操作方面的问题以及老化测试标准。 相似文献
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White lupin is an annual crop that has been used for phytostabilization of acidified multicontaminated (heavy metals and As)
soils from the Aznalcóllar spill-affected area, Southern Spain. One of the most important factors for successful phytostabilization
is monitoring the pollutant bioavailability in the soil. The aim of this work was to determine the best-suited method for
assessing the bioavailability of heavy metals together with As in the Aznalcóllar spill-affected area, by means of a systematic
comparison between different extraction methods (Ammonium bicarbonate-diethylenetriamine pentaacetic acid (AB-DTPA), CaCl2, NaNO3, BCR, (NH4)2SO4 and rhizo). Both AB-DTPA and the first step of the BCR method were found to be unsuitable for assessing the bioavailability of heavy
metals and As to plants growing in acidic soils. However, CaCl2-extractable As, Cu, and Zn and NaNO3-extractable As and Zn were well correlated with their concentrations in plant organs. Rhizo and (NH4)2SO4, with the highest determination coefficients, were the most recommended simple extraction methods to assess the bioavailability
of As, Cu, Fe, Mn, and Zn in acidified multicontaminated soils using white lupin as an excluder model plant. 相似文献