Satellite detection of land-use change and effects on regional forest aboveground biomass estimates

We used remote-sensing-driven models to detect land-cover change effects on forest aboveground biomass (AGB) density (Mg.ha(-1), dry weight) and total AGB (Tg) in Minnesota, Wisconsin, and Michigan USA, between the years 1992-2001, and conducted an evaluation of the approach. Inputs included remotely-sensed 1992 reflectance data and land-cover map (University of Maryland) from Advanced Very High Resolution Radiometer (AVHRR) and 2001 products from Moderate Resolution Imaging Spectroradiometer (MODIS) at 1-km resolution for the region; and 30-m resolution land-cover maps from the National Land Cover Data (NLCD) for a subarea to conduct nine simulations to address our questions. Sensitivity analysis showed that (1) AVHRR data tended to underestimate AGB density by 11%, on average, compared to that estimated using MODIS data; (2) regional mean AGB density increased slightly from 124 (1992) to 126 Mg ha(-1) (2001) by 1.6%; (3) a substantial decrease in total forest AGB across the region was detected, from 2,507 (1992) to 1,961 Tg (2001), an annual rate of -2.4%; and (4) in the subarea, while NLCD-based estimates suggested a 26% decrease in total AGB from 1992 to 2001, AVHRR/MODIS-based estimates indicated a 36% increase. The major source of uncertainty in change detection of total forest AGB over large areas was due to area differences from using land-cover maps produced by different sources. Scaling up 30-m land-cover map to 1-km resolution caused a mean difference of 8% (in absolute value) in forest area estimates at the county-level ranging from 0 to 17% within a 95% confidence interval.     

Study on Community Diversity of Coastal Shelter Forest in Jiaonan

Evaluating the biodiversity of previous and current species in a forest community is an important task. Some methodological researches and effective applications have been carried out widely in the temperate upland zone. However, they lack related researches in coastal shelter forests. This paper attempts to analyze them for Jiaonan coastal forest communities from the following three aspects, the relationship between plant biodiversity structure and its environment, the nexus between biodivers…     

Land Degradation Evaluation in North Hebei Province Based on Remote Sensing and GIS

Abstract

Land degradation is one of the serious environmental problems that can lead to poverty, and is especially prominent in eco-fragile areas in developing countries and increases the risk of environmental safety. North Hebei Province belongs to an ecologically fragile region in North China, which has great impact on the eco-safety of Beijing and Tianjin. Using Landsat TM data and GIS, this paper evaluates land degradation in North Hebei province of China from the the 1960's to 1987 and 2000. Land use/cover change pattern from 1987 to 2000, its regional difference and forest change characteristics will also be analyzed; soil erosion intensity and arable land suitability were also evaluated. Results revealed that land use/cover pattern in this study area did not change greatly from 1987 to 2000. The structure and function of regional land ecosystem was at a level of local improvement and integral deterioration. Land above medium soil erosion intensity reached 21 percent, which was also the area with a serious soil erosion and land degradation problem. Soil erosion and land degradation intensity of grassland was the biggest. For the present arable land, the proportion of high suitability was 13 percent.     

Treatment of tannery wastewater by electrocoagulation

Treatment of tannery wastewater by electrocoagulation with low cell current(≤1A)and soluble electrodes(mild steel electrodes and aluminum electrodes)was studied.Compared with aluminum electrodes,mild steel electrodes were more effective for the removal of sulfide,with a removal efficiency of over 90%.But during the treatment process,black color precipitate typical to iron(Ⅱ)sulfides was produced.While aluminum electrodes were effective to eliminate the colority of the effluent,the removal efficiency of sulfide was lower than 12%.The mechanisms of the removal of chemical oxygen demand,ammonia,total organic carbon,sulfide and colority with the two soluble electrodes(mild steel and aluminum electrodes)were discussed in detail.In order to exert the predominance of diffenent types of electrodes,the tannery wastewater was treated using mild steel electrodes first followed by the filter and finally by the aluminum electrodes,the elimination rates of chemical oxygen demand,ammonia,total organic carbon,sulfide and colority were 68.0%,43.1%,55.1%,96.7% and 84.3%,respectively,with the initial concentrations 2413.1 mg/L,223.4 mg/L,1000.4 mg/L,112.3 mg/L and 256 dilution times,respectively.The absorbance spectra and energy consumption during electrocoagulation process were also discussed.     

全氟辛烷磺酸(PFOS)对人骨髓间充质干细胞PPARs亚型及分化潜能的影响

过氧化物酶体增殖物激活受体(peroxisome proliferators-activated receptors,PPARs)是全氟辛烷磺酸(perflurooctane sulfon-ate,PFOS)的首要分子靶标,但PPARs各亚型在PFOS毒性效应中可能产生不同调控作用,相关机理并不清楚.本研究采用人骨髓间...     

具有超压/负压防护功能的急救车防生物污染的安全性试验研究

采用粘质沙雷菌气溶胶,对具有超压/负压防护功能的急救车防生物污染的安全性进行试验考核。分别测试气溶胶发生后30s,1min,5min,10min时,车厢在超压防护和负压防护下的过滤效率,其结果表明:急救车在超压防护状态下开启空调时的平均过滤效率能达到99.99%,不开空调时的平均过滤效率能达到99.95%;在负压防护状态下开启空调时的平均过滤效率能达到99.93%,不开空调时的平均过滤效率能达到99.95%。证明急救车能够通过生物污染区域安全运送、急救伤病员,也能够运送、急救生物污染伤病员或烈性传染病员确保沿途环境不受污染,该研究成果为应对生物恐怖袭击和突发公共卫生事件(烈性传染病)提供了一种安全可靠的机动医疗救治平台。     

我国危险化学品企业搬迁方案研究

概要地对我国现有危险化学品企业安全防护距离不足的现状进行分析,提出危险化学品企业搬迁工作实施的基本原则,探讨危险化学品企业搬迁范围的确定、厂址的解决、资金的分配、政策的制定和长效机制的建立等问题。建议搬迁企业在政府的统一规划下,坚持以人为本,坚持安全生产和可持续发展的原则,在搬迁中提高技术含量和社会形象,增强市场竞争力。针对我国危险化学品企业的特点提出了一套搬迁方案和步骤。论文的研究成果将为各地政府指导当地危险化学品企业进行科学规划,对待搬迁的危险化学品企业实现安全有效搬迁及健康发展提供了有益参考。     

巧用Premiere Pro 2.0 制作艺术倒计时片头

Premiere Pro 2.0 是用于编辑影视作品的专业软件,可以编辑和制作电影、DV、栏目包装、字幕、网络视频、电子相册等.本文介绍了其自带的制作倒计时片头效果模板的使用方法,提出了利用Premiere Pro 2.0视频转场特效结合专业制图软件制作艺术倒计时效果的具体方法.     

Land Use,Geology, Enrichment,and Stream Biota in the Eastern Ridge and Valley Ecoregion: Implications for Nutrient Criteria Development1

Abstract: The eastern panhandle region of West Virginia is entirely within the Appalachian Ridge and Valley ecoregion. It is underlain by limestone in the eastern part and by shale and sandstone in the western part. Agricultural and urban development has affected the condition of the streams of this region. We examined samples from 165 stations in the Ridge and Valley, collected from 1998 to 2004. Land use, geological characteristics, physical and chemical parameters, and algal and macroinvertebrate assemblages were used to identify potential stressors that affect streams in the region. Our analyses indicated that both human land uses and ecoregional differences led to elevated nutrient concentrations in streams of the study areas. Multiple regression analyses indicated that both agricultural and urban land use in the watershed were associated with high nutrient concentrations (NO₂₊₃, total nitrogen, and total phosphorus) in streams. These elevated nutrient concentrations have led to increased algal biomass, increased trophic state, and degradation of macroinvertebrate community in the streams. Values of the West Virginia Stream Condition Index, as well as several other benthic macroinvertebrate metrics, decreased with increased nutrient concentrations and conductivity, especially in the limestone region. When regional differences were partitioned out in the analysis, nutrient concentrations became the strongest stressor in the limestone region while conductivity exhibited less of an effect on macroinvertebrate metrics. Meanwhile, periphyton diagnostic metrics also responded to increased nutrient concentrations, suggesting nutrients could be a cause of biological degradation in the Eastern Ridge and Valley region. Multiple approaches and multiple lines of evidence (reference approach and stressor‐response approach) were applied to develop nutrient benchmarks for different geological regions in the study watershed.