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91.
植物原位阻截铅锌矿区土壤重金属效果和配置模式研究   总被引:2,自引:1,他引:1  
为了研究铅锌矿区植物原位阻截土壤废渣重金属效果和配置模式,采用多种植物栽培和径流小区收集水样测定的方法,3年生植物的研究结果表明:苎麻、苦楝、构树可降低废弃尾沙坝地表径流水中重金属Pb负荷输出9.04%~9.64%。栾树、构树、芦苇、苦楝、刺槐可降低地表径流水中重金属Cd负荷输出67.0%~75.86%,构树、高羊茅、刺槐、栾树、芦苇、狗牙根、五节芒可降低地表径流水中重金属Cu负荷输出52.64%~70.97%,刺槐、女贞可降低地表径流水中重金属Zn负荷输出74.99%~78.35%;在重金属污染林地,刺槐可降低地表径流水中重金属Pb负荷输出40.96%,苦楝可降低地表径流水中重金属Cd负荷输出60.42%。构树通过植物富集,可以使铅锌尾矿区尾沙中Pb、Cd、As、Zn的含量分别降低31.87%、41.28%、29.48%、38.45%;女贞可以使铅锌尾矿区尾沙中Pb、Cd、As、Zn的含量分别降低27.31%、39.52%、33.47%、27.59%。植物原位阻截和修复重金属机理一是植物富集了土壤中重金属,二是植物使土壤中重金属形态发生了变化,这种机理有待进一步研究。  相似文献   
92.
Reasons for performing study: Sarcoids are nonmetastasising, yet locally aggressive skin tumours that constitute the most frequent neoplasm in equids. Infection by bovine papillomaviruses types 1 and 2 (BPV‐1, BPV‐2) has been recognised as major causative factor in sarcoid pathogenesis, but a possible correlation of intralesional virus load with disease severity has not been established thus far. Hypothesis: Given the pathogenic role of BPV‐1 and BPV‐2 in sarcoid disease, we suggest that intralesional viral DNA concentration may reflect the degree of affection. Methods: Severity of disease was addressed by recording the tumour growth kinetics, lesion number and tumour type for 37 sarcoid‐bearing horses and one donkey. Viral load was estimated via quantitative real‐time PCR (qPCR) of the E2, E5, L1 and L2 genes from the BPV‐1/‐2 genome for one randomly selected lesion per horse and correlated with disease severity. Results: Quantitative PCR against E2 identified viral DNA concentrations ranging from 0–556 copies/tumour cell. Of 16 horses affected by quiescent, slowly growing single tumours or multiple mild‐type lesions, 15 showed a viral load up to 1.4 copies per cell. In stark contrast, all equids (22/22) bearing rapidly growing and/or multiple aggressive sarcoids had a viral load between 3 and 569 copies per cell. Consistent results were obtained with qPCR against E5, L1 and L2. Conclusions: While tumours of the same clinical type carried variable virus load, confirming that viral titre does not determine clinical appearance, we identified a highly significant correlation between intralesional viral load and disease severity. Potential relevance: The rapid determination of BPV viral load will give a reliable marker for disease severity and may also be considered when establishing a therapeutic strategy.  相似文献   
93.
提出了一种基于优化灰色模型的农村季节性电力负荷预测方法:首先对原始的时间序列数据进行移动平均处理,然后分别建立多个灰色GM(1,1)模型并进行优化组合.实例研究结果表明,该方法具有较高的预测精度。  相似文献   
94.
Lianas hold an important, but understudied, role in forest dynamics, however they are difficult to measure and detailed liana measurements are time consuming. Many researchers have therefore used an ordinal scale index, the crown occupancy index (COI), to describe the liana load carried by trees. Here we assess the overall effectiveness, in terms of accuracy, precision, repeatability and efficiency, of the COI in tropical forests. We relate the COI to more detailed liana measurements at the individual tree-level and site-level, comparing sites with different levels of liana infestation. Our results show (1) that the COI accurately measures individual tree and plot level liana loads, indicated by the strong correlations between the COI and the number and basal area of lianas. However, (2) as expected, the COI is only weakly related to the basal area of lianas rooted close to the tree, which is a proxy for competition for below-ground resources. The COI is also (3) an efficient measure of liana loads, as the input time needed for a COI survey is considerably less than that of a detailed liana survey. We also (4) found a high degree of repeatability in COI classification between observers. Additionally (5), the COI can be used to differentiate between sites in terms of their overall liana canopy competition (precision), but (6) may not be a precise indicator of the site-level mean basal area of lianas in tree crowns.  相似文献   
95.
The model projected ecosystem carbon dynamics were incorporated into the default (contemporary) fuel load map developed by FCCS (Fuel Characteristic Classification System) to estimate the dynamics of fuel load in the Southern United States in response to projected changes in climate and atmosphere (CO2 and nitrogen deposition) from 2002 to 2050. The study results indicated that in 2002 the total fuel load of the Southern United States was about 1.15 P g (1 P = 1015), which will decrease to 1.11 P g in 2050. The declination of fuel load is mainly due to the climate change, especially the reduced precipitation in 2050, while the effects of elevated CO2 and nitrogen deposition will increase fuel load. Interactions among all factors will result in 1% reduction in the fuel load in 2050. In response to the spatial heterogeneity in environmental changes, the dynamics of fuel load from 2002 to 2050 vary strongly among the study states. The declined precipitation in the northern inland of the study region may lead to 20% fuel load reduction in Tennessee and Kentucky by the year of 2050, while the elevated precipitation and decreased daily mean temperature in the coastal states, especially in South Carolina, North Carolina, and Virginia, may result in fuel load accumulation. The temporal–spatial variation of the fuel load may be overestimated since the adjustments of forest management regime in response to climate change were not considered in current study.  相似文献   
96.
肖海  吕子奇  向凯  彭国强  陈东立 《安徽农业科学》2010,38(30):17204-17207
为了解决预测森林火灾以及森林火灾发生之后的人员及设备的合理调度问题,基于ArcGIS Engine构建森林防火与应急决策支持系统。在此系统平台上,在没有发生火灾的情况下利用AHP法结合火险天气等级进行预测预报、设置最佳观测站位置等,在火灾发生时利用GPS对火点进行精确定位,并将接收到的数据在三维场景中进行动态火势模拟,实时观测火势蔓延态势。此外,将王正非林火蔓延模型进行优化,以便更准确地模拟林火的蔓延,当火灾发生后可进行统计分析并进行损失评估。结果表明,采用王正非林火蔓延模型结合ArcGIS Engine三维分析,对森林火灾蔓延态势的掌握达到了较高的准确度。  相似文献   
97.
巢湖流域规模化畜禽养殖场污染现状与环境管理对策   总被引:5,自引:1,他引:4  
彭军  司友斌  张震 《安徽农业科学》2010,38(1):314-316,471
[目的]调查巢湖流域的畜禽养殖业现状及其污染情况,提出应对措施。[方法]通过对巢湖市畜牧局的统计资料调查及对部分养殖小区的污染状况调查,分析了巢湖流域规模化畜禽养殖业的污染现状,提出了相应的环境管理和防治对策。[结果]目前巢湖流域畜禽养殖业产生的各类污染物数量巨大。将调查所得巢湖流域各类畜禽的粪便均换算为猪粪当量,并根据畜禽日排泄量,推算出该流域全年畜禽粪便共达2515.35万t,BOD为102.46万t、COD为85.64万t,产生的氨氮达11.70万t。巢湖流域规模化养殖场数目较多(居巢区为133个)、养殖种类多、过于分散、规模化程度较小(以猪为倒,平均为176头)。[结论]针对该流域畜禽养殖场污染问题提出几争适合巢湖流域规模化畜禽养殖业的环境管理对策.  相似文献   
98.
ZHOU Li  CHEN Shan  ZHANG Di-kai 《园艺学报》2010,26(12):2482-2486
Human papillomavirus (HPV) genital infection is a very common sexual transmitted disease. Mostly, the infection is transient and asymptomatic. The induction of effective immune responses usually allows the infection to be spontaneously cured. However, the infection sometimes can be responsible for an intraepithelial lesion, which may progress to be cervical cancer. Cervical cancer is one of the most common neoplastic diseases affecting women. It is clear that carcinogenic HPV infection is the necessary process for the development of cervical cancer. HPV infection is very frequent in young women aged less than 25 years and viral clearance lasts for 8 months in average. This clearance is the consequence of host immunity intervention, which leads to spontaneous regression of infection and the overwhelming majority of low-grade squamous intraepithelial lesions (more than 80% within a period of 2 years). The major factor, which permits the progression to high grade squamous intraepithelial lesions and invasive cervical cancer, is the persistent feature of HPV infection. HPV infection is usually transient, but several factors were identified as host factors (genetic, immunodepression, oral contraception and smoking) and viral factors (genotype, variants, viral load and integration) to increase the persistence. Cervical cancer is clearly the first virus-induced solid tumor discovered in human. Furthermore, it represents a woman death cause that can be avoided.  相似文献   
99.
The relationship between 9,10-ketol-octadecadienoic acid (KODA), GAs and jasmonic acid (JA) and flower bud formation influenced by fruit load in apples (Malus domestica Borkh.) was investigated. The endogenous KODA and JA concentrations in apical buds in plants subjected to flower thinning treatment (FTT), under which all flowers were removed were higher than those in plants subjected to heavy crop treatment (HCT), under which the number of leaves per fruit was adjusted to 20 from 60 to 120 days after full bloom (DAFB). In contrast, the gibberellic acid concentrations [total of gibberellin A1 (GA1) and gibberellin A4 (GA4)] in FTT plants were low compared with those in HCT plants. The result suggests that KODA and JA in contrast to GAs may have opposite effects on flower bud formation which is significantly influenced by fruit load in apples and that KODA and JA may also be associated with flower bud formation in apples.  相似文献   
100.
库车小白杏树体负载量与坐果关系的研究   总被引:1,自引:1,他引:0  
针对新疆库车小白杏坐果率低的问题,研究了不同树体负载量与坐果之间的关系。结果表明:调查树体的长果枝比率高于中果枝和短果枝,而长果枝的坐果率在4类果枝中是最低的,50%和70%疏花处理以及花期喷施营养液可以显著提高坐果率,4种类型果枝的完全花比例依次为中果枝花束状果枝短果枝长果枝。说明长果枝由于其本身生长较旺负载量较轻,导致树体营养生长和生殖生长失衡,并且形成较多的败育花,从而产生较低的坐果率。而通过疏花和补充营养可以在一定程度上缓解营养生长与生殖生长之间的矛盾,提高坐果率。  相似文献   
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