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生物质炭协同伴矿景天-玉米间作修复锌镉复合污染土壤研究 总被引：2，自引：0，他引：2
通过盆栽试验,研究了添加不同比例生物质炭(0%、1%、2%、5%)条件下伴矿景天和玉米在单、间作种植模式时的生长状况及其对锌镉复合污染土壤的修复效果。结果表明:(1)添加生物质炭可以显著降低土壤中的重金属有效性,伴矿景天与玉米各部位锌镉含量均随着施加生物质炭量的增加而降低,伴矿景天的生长亦受到抑制,但添加5%生物质炭时与伴矿景天间作的玉米生物量最大。(2)在不添加生物质炭条件下,伴矿景天与玉米间作将土壤中的锌镉含量降至国家二级标准(GB15618-1995)以下所需时间最短,分别为4.73和2.77年;在添加5%生物质炭条件下与伴矿景天间作的玉米可取得最佳收益,但土壤锌镉含量降至国家二级标准以下的时间要延长至13.07和8.31年。在适当牺牲修复时间的前提下,采用伴矿景天与玉米间作结合施加适量生物质炭的修复技术是一种锌镉复合污染土壤"边生产、边修复"可行的修复模式,为我国重金属污染土壤修复工程实践提供理论基础。 相似文献
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几种含硫肥料对油菜和三叶鬼针草吸收铅镉的影响 总被引：1，自引：0，他引：1
通过盆栽实验,研究4种含硫肥料对2种镉富集能力较强的植物——油菜和三叶鬼针草在铅、镉复合污染土壤中吸收铅、镉的影响.结果表明,硫磺和(NH4)2SO4增加了油菜对铅的吸收量,含硫肥料降低了三叶鬼针草对铅的吸收.硫磺和(NH4)2SO4增加了油菜对镉的吸收量,含硫肥料对三叶鬼针草吸收镉没有显著影响.在铅、镉复合污染土壤中,硫磺和(NH4)2SO4可以作为有效的肥料提高油菜对铅或镉的吸收,而对于三叶鬼针草,添加含硫肥料不能促进其提高对铅、镉的吸收. 相似文献
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玉米杂交种产量比较及主要农艺性状的相关分析 总被引：1，自引：0，他引：1
本实验选用了九个杂交种及两个对照：366＊368,397＊398,399＊403,400＊403,401＊403,402＊403,408＊408,9702,吉单180（CK1）,本育9（CK2）。采用随机区组设计。通过对各种杂交种的产量和综合农艺性状的分析,比较出了一些较优的杂交组合方式,又在通过对产量,千粒重,出籽率,穗长,穗粗等农艺的相关分析得到了对产量影响最大的是千粒重（r=0.5895＊）相关系数达显著水平。穗粗（r=0.2064）,出籽率（r=0.3075）和穗长（r=0.2828）与产量呈相关。性状之间株高与穗位高和茎粗（r=0.7249,r=0.7726＊＊）之间呈极显著正相关。因而提高千粒重,增加穗粗和穗长,提高出籽率并兼顾其他农艺性状是提高玉米产量的有效途径。 相似文献
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不同土地利用类型下土壤-作物镉含量积累及其健康风险分析 总被引：3，自引：0，他引：3
镉(Cd)是一种剧毒重金属元素,可引起呼吸系统、肾损伤等多种疾病,对人体毒性极高,可通过多种途径暴露于人体,危害人体健康。土壤-植物-食品-人的迁移途径在人类对环境镉的暴露中占主导地位。近年来,Cd通过饮食途径对人体健康造成的风险日益引起人们的关注和重视。本文在对研究区不同土地利用类型下土壤和作物进行大规模采样调查的基础上,对其蔬菜、水稻、旱地、果园等4种土地类型土壤及其种植作物中镉含量积累进行了研究。结果表明,菜地和水稻地有明显的污染超标现象,其中菜地土壤镉含量最高。根据不同土地利用类型下各作物镉富集系数,进行聚类分析,比较其对镉富集能力的差异,结果表明水稻地稻米镉的富集能力最高,单独划为一类。利用定性风险分析技术,对不同土地利用类型下土壤镉对人体健康的风险商值进行了计算,结果表明不同土地类型下,作物镉风险商值为水稻>深色蔬菜>浅色蔬菜>水果>玉米。镉对个人致癌年风险的计算结果表明,水稻个人年致癌风险为0.6270×10-4/年,高于防护委员会(ICRP)推荐的最大可接受年风险水平0.5×10-4/年,为不可接受水平,居民面临较大的致癌风险,应采取积极措施对研究区土壤镉污染进行治理和修复。 相似文献
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纳米硒对断奶仔猪生长和免疫的影响 总被引：5，自引：0，他引：5
将纳米硒和亚硒酸钠2种硒源分别以0．1、0．2、0.3、0．4、0．5、1．0mg／kg6个硒水平添加到基础日粮中，配制成12种试验日粮，基础日粮作对照，研究纳米硒和亚硒酸钠对仔猪生长和免疫的影响。结果显示：（1）亚硒酸钠添加浓度在0.2～0．5mg／kg硒添加水平范围内仔猪生长性能处于高峰平台，1．0mg／kg硒添加水平仔猪生长性能显著低于0．2～0．4mg／kg硒添加水平。纳米硒添加浓度在1．0mg／kg，仔猪生长性能仍然保持在高峰平台。硒源添加浓度在0．1～0．3mg／kg时，亚硒酸钠和纳米硒对仔猪生长性能的影响无显著差异；硒源添加浓度在0．4～1．0mg／kg时，纳米硒组仔猪生长性能显著高于亚硒酸钠组。（2）硒添加浓度在0．1-0．3mg／kg时．两种硒源对血清免疫球蛋白IgG和IgM含量、抗体生成细胞数、巨噬细胞吞噬率、天然杀伤细胞活性的影响差异不显著：硒添加浓度在0．4～1．0mg／kg硒时，纳米硒组的上述指标显著高于亚硒酸钠组。（3）硒显著提高了免疫器官指数和血清免疫球蛋白IgA含量，两种硒源和硒添加水平对之没有显著影响。上述结果提示．纳米硒的Weinberg剂量-效应的最适剂量范围宽于亚硒酸钠．对仔猪的安全性更高。 相似文献
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纳米硒对肉鸡肌肉品质的影响 总被引：4，自引：0，他引：4
本实验以亚硒酸钠为对照,研究了纳米硒对肉鸡肌肉品质的影响。岭南黄公母混合雏780羽按饲养试验要求分为13组,每组4个重复,每个重复15羽。将纳米硒和亚硒酸钠2种硒源分别以0.1、0.2、0.3、0.4、0.5、1.0 mg/kg 6个硒水平添加到基础日粮中,基础日粮作对照。结果显示:(1)纳米硒添加浓度在0.20-1.0 mg/kg胸肌滴水损失始终保持在低峰平台。硒源添加浓度在0.40-1.0 mg/kg硒时,纳米硒组胸肌滴水损失显著低于亚硒酸钠组(P<0.05)。(2)硒源添加浓度在0.10-0.40 mg/kg时,两种硒源对胸肌GSH-Px活性的影响无显著差异(P<0.05);在0.50和1.0 mg/kg硒添加水平上,纳米硒组GSH-Px 活性显著高于亚硒酸钠组(P<0.05)。硒源添加浓度在0.40-1.0 mg/kg硒时,纳米硒组T-AOC显著高于亚硒酸钠组(P<0.05),MDA含量显著低于亚硒酸钠组(P<0.05)。(3)不加硒的空白组胸肌硒含量显著低于加硒组。硒源添加浓度在0.10-0.30 mg/kg时,两种硒源对胸肌硒含量的影响无显著差异;在0.40- 1.0 mg/kg硒添加水平上,纳米硒组胸肌硒含量显著高于亚硒酸钠组。上述结果提示,纳米硒的Wein berg剂量-效应的最适剂量范围要宽于亚硒酸钠,高剂量添加时比亚硒酸钠更能提高肌肉组织抗氧化能力,降低肉的滴水损失;肌肉硒沉积率优于亚硒酸钠。 相似文献
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目的:评价枇杷清肺饮加减对比抗菌类药物治疗寻常型痤疮的临床疗效。方法:检索维普资讯中文科技期刊数据库、CNKI中国期刊全文数据库,万方医学网数据库、Pubmed数据库。将符合纳入标准的5篇文献、495位患者的临床疗效进行Meta-分析。Meta-分析的软件为Cochrane协作网免费提供的Revman5.2专用软件。结果:对纳入的随机对照试验的有效数据进行异质性检验,X2=6.27,P=0.18,大于显著性检验水准0.05,故进行固定效应模型分析,结果 5篇文献的疗效评价及效应量OR=4.92,95%的CI为[2.72,8.92],效应合并值的假设检验:Z=5.25,P0.00001,提示枇杷清肺饮汤加减比抗菌类药物治疗寻常型痤疮的有效率高。对纳入的随机对照试验的治愈数据进行异质性检验,X2=5.78,P=0.22,大于显著性检验水准0.05,故进行固定效应模型分析,结果纳入文献的疗效评价及效应量OR=2.79,95%的CI为[1.87,4.17],效应合并值的假设检验:Z=5.01,P0.00001,提示枇杷清肺饮汤加减比抗菌类药物治疗寻常型痤疮的治愈率高。结论:现有资料的Meta-分析,治疗组及对照组在同等的治疗方案下,治疗组中加入枇杷清肺饮加减,对照组中加入单一一种抗菌类药物,治疗组可以显著提高治疗寻常型痤疮的有效率及治愈率。 相似文献
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本文讨论了滦平试区春玉米在不同水分条件下的肥料——产量效应和不同肥力条件下的水分——产量效应。研究结果表明，在中等肥力条件下，水分——产量效应接近显著水平，而肥料一产量效应在任何水分条件下均为正效应。作者认为，在目前生产力水平条件下，限制产量的主导因素是旱地、春玉米、水肥效应 相似文献
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Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
12.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
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Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
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Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
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Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献
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Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
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Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
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《中国科学院院刊(英文版)》2014,(3)
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence 相似文献
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Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels 总被引：1，自引：0，他引：1
《中国科学院院刊(英文版)》2014,(3):267-268
<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese 相似文献
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WANG Sijia 《中国科学院院刊(英文版)》2014,(2):192-194
<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages. 相似文献