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排序方式: 共有596条查询结果,搜索用时 15 毫秒
1.
In this paper, we assert and test the proposition that environmental disclosure (ED) is structured by institutionalised myths and that is why ED is decoupled from environmental performance and media pressures. Focusing on firms from Canada, France and Germany, findings show that ED mimetic isomorphism for different topics varies among countries and by industry sensitiveness to the environment. The results corroborate the institutional presumption that institutionalised myths vary among different contexts. Our findings also suggest that institutionalised ED structures may not reflect environmental performance, mimetic patterns being affected by environmental performance. However, the decoupling between ED mimetic isomorphism and environmental performance decrease when firms’ ED credibility is questioned by the media.  相似文献   
2.
This paper responds to recent calls for alternative approaches to the analysis of environmental communication that uncover overlooked voices in the discussion of environmental issues. Borrowing core principles from critical rhetoric, it suggests a way to categorize media messages according to how human–nature relationships are constructed in media discourse. The paper illustrates how, in presenting contrasting and often oppositional constructions of human–nature relationships, the media messages examined articulate three recurrent (but not equal) discourses on global warming. These discourses include (1) nature-as-out-of-reach discourse, (2) nature-as-antagonist discourse, and (3) nature-as-co-present discourse. By juxtaposing these discourses, the paper shows how environmental communication scholars can engage in critical realism and political advocacy to illuminate latent public discourse that holds the potential to champion marginalized voices of nature and accentuate the interconnectedness of humans and the environment.  相似文献   
3.
为识别公众风险感知的演化规律和官方媒体参与的作用机制,首先,根据公众的行为表现划分不同风险感知群体,并分析群体间的相互竞争和官方媒体的扰动作用;然后,通过扩展Lotka Volterra模型建立群体间的相互竞争模型;在此基础上,通过推导模型平衡点及其稳定性分析模型演化规律;最后,运用数值仿真考查了官方媒体的参与对模型演化的影响。研究结果表明:模型演化具有3种结果情景,官方媒体参与能够显著改变模型演化的速度和结果。  相似文献   
4.
Wildlife provides food, medicine, clothing, and other necessities for humans, but overexploitation can disrupt the sustainability of wildlife resources and severely threaten global biodiversity. Understanding the characteristics of consumer behavior is helpful for wildlife managers and policy makers, but the traditional survey methods are laborious and time-consuming. In contrast, culturomics may more efficiently identify the features of wildlife consumption. As a case study of the culturomics approach, we examined tiger bone wine consumption in China based on social media and Baidu search engine data. Tiger bone wine is one of the most purchased tiger products; its consumption is closely related to tiger poaching, which greatly threatens wild tiger survival. We searched a popular social media website for the term “tiger bone wine” and focused on posts that were originally created from 1 January 2012 to 31 December 2018. We filtered and classified posts related to the purchase, sale, or consumption of tiger bone wine and extracted information on providers, consumption motivations, year of production, and place of origin of the tiger bone wines based on the texts and photos of these posts. We found 756 posts related to tiger bone wine consumption, 113 of which mentioned providers of tiger bone wine, including friends (53%), elder relatives (37%), peer relatives (7%), and others (3%). Out of the 756 posts, 266 indicated the motivations of tiger bone wine consumption. Tiger bone wines were consumed as a tonic (34%), medicine (23%), game product (30%), and a symbol of wealth (28%). Some posts indicated ≥2 consumption motivations. These findings were consistent with the search queries from Baidu index. Such information could help develop targeted strategies for tiger conservation. The culturomics approach illustrated by our study is a rapid and cost-efficient way to characterize wildlife consumption.  相似文献   
5.
为研究管道内金属丝网对甲烷/空气预混火焰传播的影响,通过实验和三维数值模拟研究安装金属丝网的管道内火焰传播特性以及流场、温度场的变化。结果表明:40目4层的金属丝网可以使火焰淬熄,30目4层的金属丝网无法淬熄,但可以使火焰停滞3 ms;大涡模型可以很好地对管道内火焰淬熄现象进行模拟;当火焰穿过30目4层金属丝网时,速度增大,在Kelvin Helmholtz不稳定和Rayleigh Taylor不稳定的耦合作用下形成湍流;金属丝网的目数会影响热量在丝网层中的扩散,当金属丝网为30目4层时,火焰热量扩散快,而当金属丝网为40目4层时,火焰热量扩散慢且温度大幅度衰减,衰减率达到83%。  相似文献   
6.
There is limited knowledge of the mechanisms that can inspire people's concern and engagement in the protection of unpopular and unappealing species. We analyzed Polish people's interest in themed internet memes featuring the proboscis monkey (Nasalis larvatus) and the consequences of this interest for conservation marketing. We examined Google Trends data, used Google Search, and searched popular media materials to estimate interest in the proboscis monkey in Poland. Photos of the proboscis monkey when presented with humor in internet memes attracted as much interest as usually more popular species (e.g., koala, panda, and orangutan) used in marketing by nongovernmental organizations. Amusing internet memes spread by social media positively correlated with increasing interest in the unappealing species, such as proboscis monkey. Interest in amusing internet memes positively correlated with individuals’ decisions to donate to 6 crowdfunding actions. Thus, conservation marketing that includes amusing memes and social media may provide a worthwhile complement to traditional campaigns and are likely to influence individuals who are unaffected by the usual means.  相似文献   
7.
总氮超标是大部分水源水库具有的共性水质问题.在外源污染得到有效控制,上游来水氮负荷较低的情况下,底泥內源氮释放对上覆水体水质影响巨大.因此,在泥水界面处对污染底泥进行合理修复以有效抑制底泥氮释放是解决总氮超标问题、控制水源水质的关键.本研究通过模拟实验对比研究了3种不同修复方法,即覆盖填料、投加功能微生物和投加铁粉在界面处的脱氮效果.结果表明,填料覆盖技术具有更明显的脱氮效果,对氨氮的平均抑制率为83%,最高时可达92%,对总氮的平均抑制率达73%,且效果稳定.  相似文献   
8.
A series of WO3/CeO2 (WOx/CeO2) catalysts were synthesized by wet impregnation of ammonium metatungstate on a CeO2 support. The resulting solid acid catalysts were characterized by X-ray diffraction (XRD), UV-Vis spectroscopy (UV-Vis), Raman spectroscopy (Raman), in-situ Fourier transform infrared spectroscopy (in-situ FT-IR) of ammonia adsorption, NH3-TPD, H2 temperature-programmed reduction (H2-TPR), NH3/NO oxidation and activity measurements for NOx reduction by NH3 (NH3-SCR). The results show that polytungstate (WOx) species are the main species of tungsten oxide on the surface of ceria. The addition of tungsten oxide enhances the Brönsted acidity of ceria catalysts remarkably and decreases the amount of surface oxygen on ceria, with strong interaction between CeO2 and WOx. As a result, the N2 selectivity of NH3 oxidation and NH3-SCR at high temperatures (> 300℃) is enhanced. Therefore, a wide working temperature window in which NOx conversion exceeds 80% (NOx conversion > 80%) from 200 to 450℃, is achieved over 10 wt.% WOx/CeO2 catalyst. A tentative model of the NH3-SCR reaction route on WOx/CeO2 catalysts is presented.  相似文献   
9.
Comparisons of microbial community structure, in eight filter media of zeolites, anthracite, shale, vermiculite, ceramic filter media, gravel, steel slag and bio-ceramic, were undertaken by analyzing the phospholipid fatty acid (PLFA) composition. A total of 20 fatty acids in the range of C11 to C20 were determined but only 13 PLFAs were detected in steel slag. They consist of saturated fatty acids, branched fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. The variation of fatty acids was revealed in the relative proportions of these fatty acids in di erent media. The aerobic prokaryotes were the predominant group in all media. The PLFA composition showed significant di erences among the eight di erent media by Tukey’s honestly test. It was found that steel slag was significantly di erent in the microbial community as compared to other filter media, probably due to its alkaline e uent. Steel slag alone is probably not a good choice of substratum in constructed wetlands. The principle components analysis (PCA) showed that zeolites, bio-ceramic, shale and vermiculite had a similar microbial community structure while steel slag and ceramic filter media were distinct from other media.  相似文献   
10.
零价铁(ZVI)去除Cu2+的特性及机制研究   总被引:3,自引:2,他引:1  
陈玉伟  王建龙 《环境科学》2009,30(11):3353-3357
研究了零价铁去除水溶液中铜离子的影响因素及动力学特性,并利用X射线衍射(XRD)分析对反应机制进行了探讨.结果表明,当溶液中Cu2+的浓度为300 mg/L,零价铁的用量为1 g/L时,Cu2+的去除率99%.Cu2+的去除速度很快,且反应前30min零价铁去除Cu2+的过程可以用一级反应动力学方程模拟.零价铁去除Cu2+的机制主要基于氧化还原反应,Cu2+的还原产物主要为Cu和Cu2O.  相似文献   
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