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41.
目的探讨Stat1是否参与弥漫性轴索损伤(diffuse axonal injury,DAI)后神经细胞凋亡的病理生理过程。方法应用自由落体撞击模型复制大鼠DAI模型,分为正常对照组、假手术组和打击后不同时间组(6、12、24、48、72h,5d和10d)。采用HE染色和镀银染色观察大鼠脑组织的病理改变,用流式细胞检测脑组织中脑细胞的凋亡率,RT-PCR法测定脑组织中bax和bcl-2的表达变化,免疫组织化学法测定脑组织中不同脑区727位丝氨酸磷酸化的信号转导与转录激活子1(Phospho-Ser727 Stat1)的表达情况。结果DAI后HE染色未见脑挫裂伤,镀银染色可见神经轴索扭曲肿胀,个别断端膨大形成轴缩球;损伤组脑细胞的凋亡率和脑组织中bax和bcl-2 cDNA扩增产物的比值24h达到最大值,随后下降;不同脑区Phospho-Ser727 Stat1表达升高,24h达峰后下降,至10d较对照组仍有显著差异;阳性细胞主要是神经元,在不同脑区也有一定量的神经胶质细胞阳性表达。脑组织中Phospho-Ser727 Stat1表达变化与bax和bcl-2的cDNA扩增产物比值的变化具有正相关性,相关系数r为0.921。结论大鼠DAI后Stat1的激活和损伤后脑细胞的凋亡有关,应与损伤后二次打击有关。 相似文献
42.
窦艳 《黑龙江省政法管理干部学院学报》2008,(6)
语篇类型和篇章模式是篇章语言学的重要范畴。语篇根据不同的交际功能和目的可以分为不同的类型,语篇类型制约着篇章模式和篇章结构。通过对专业英语八级考试中听力讲座部分的试题材料的语篇类型和篇章模式的剖析,提出了学术讲座在篇章层面的应试策略。 相似文献
43.
Self‐driving cars (also known as driverless cars, autonomous vehicles, and highly automated vehicles [HAVs]) will change the regulatory, political, and ethical frameworks surrounding motor vehicles. At the highest levels of automation, HAVs are operated by independent machine agents, making decisions without the direct intervention of humans. The current transportation system assumes human intervention though, including legal and moral responsibilities of human operators. Has the development of these artificial intelligence (AI) and autonomous system (AS) technologies outpaced the ethical and political conversations? This paper examines discussions of HAVs, driver responsibility, and technology failure to highlight the differences between how the policy‐making institutions in the United States (Congress and the Public Administration) and technology and transportation experts are or are not speaking about responsibility in the context of autonomous systems technologies. We report findings from a big data analysis of corpus‐level documents to find that enthusiasm for HAVs has outpaced other discussions of the technology. 相似文献
44.
Polycentric Systems and Multiscale Climate Change Mitigation and Adaptation in the Built Environment
Addressing climate change requires consideration of mitigation and adaptation opportunities at multiple spatial scales. This is particularly true in the built environment, defined here to include individual buildings, neighborhoods, and the spaces between. The current U.S. political environment portends fewer resources and coordinating services for mitigation and adaptation at the federal level, however, reinforcing the relevance and necessity of actions at subnational levels. In this study, we evaluate the applicability of a polycentric model of governance to the implementation of mitigation and adaptation practices, as well as the presence of polycentric systems in the built environment. We assemble a database of practices with the potential to achieve both mitigation and adaptation objectives, as well as those that may be cross‐purposed or that may achieve one but not the other. We review practices to gauge the applicability of a polycentric model of governance to mitigation and adaptation practices in the built environment, and examine the attributes of three existing adaptation and/or mitigation programs to assess the extent to which they exhibit polycentric attributes. We conclude with recommendations for a broader research agenda, including efforts to develop more in‐depth examinations into individual programs and comparative analysis of performances of different governance attributes. 相似文献
45.
Studies show that women and girls consistently demonstrate higher levels of concern for the environment than men and boys. Separately, research also indicates that women officeholders pay particular attention to the issues prioritized by their female constituents. Interestingly, despite the consistency of the gender gap in attitudes to environmental issues the literature has paid scant attention to the role of women officeholders in the adoption of environmental policy. The goal of this paper was to start to address that lacuna. Using pooled cross‐sectional time series analyses of environmental standards in 18 Western parliamentary democracies (1990–2012), our initial findings indicate women officeholders are associated with the adoption of higher environmental standards. 相似文献
46.
The reform of the EU Emissions Trading System (ETS) adopted in November 2017 was surprisingly strong, given the previous opposition from central member‐states like Poland and key stakeholders like the energy‐intensive industries. The carbon price has also increased substantially since then. To explain why such major reform was possible, we present several findings with wider relevance. Importantly, all the actors pushing for a more ambitious reform benefitted from having a central, “second‐best” mechanism in place—the Market Stability Reserve (MSR)—which could be further tightened. By focusing cancelation on allowances in the MSR and taking place only after 2023, policy entrepreneurs managed to make the distribution of costs obscure and diffuse, whereas the benefits (a probable higher carbon price and related greater auctioning revenues for member‐states) were more specific and closer in time. That is what we call “smokescreen politics.” 相似文献
47.
Seismologists have reported that a majority of recent earthquakes in Oklahoma have been triggered by the activities of oil and gas companies. Despite this fact, there is evidence of strong opposition toward earthquake mitigation policy. In this article, we argue that how individuals define issues affect their policy choice. Furthermore, we incorporate the concept of venue shopping from the literature on macro theories of the policy process to investigate the effect of problem definition in shaping individual venue preference for policy choice. Using unique survey data, we find that problem definition, particularly issue causality and issue image, is strongly related to individual support for earthquake mitigation policy. However, a more nuanced relationship between individual problem definition and venue preference is observed. Our findings contribute to scholarly endeavors to understand the politics of problem definition at an individual level, which may be the precursor of understanding policy choices at the institutional level. 相似文献
48.
Since its inception in 2009, Uber has grown into a technology behemoth, with operations in over 70 countries and 500 cities around the world. Along the way, it has successfully forced regulatory upheaval in hundreds of local taxi markets controlled by municipal authorities. In this sense, Uber is not only a market disruptor, but also a policy disruptor. This paper examines the nature of such policy disruption at the local level by reviewing regulatory responses to Uber in ten North American cities. We find that regulatory outcomes are a function of two factors: Uber’s government relations strategy, either cooperative or confrontational, and the degree to which local governments perceive Uber as complementary or harmful to the existing marketplace. We conclude by proposing a typology of regulatory responses to Uber as a basis to identify patterns in the behavior of municipal regulatory authorities and political leaders. 相似文献
49.
Among the more recognizable programs related to natural and sustainable food is the United States Department of Agriculture’s National Organic Program. Although the robustness of the organic food market is difficult to contest, many debate the extent to which U.S. organic policy outcomes adequately serve consumers and the organic agriculture producers they rely on. This paper engages the debate from the perspective of certified organic producers. Drawing on the results of a nationwide survey of USDA‐certified producers, we first provide a snapshot of how producers assess the environmental, consumer, and market impacts of U.S. organic food policy. We then examine the extent to which organic producers’ policy impact perceptions are associated with their alignment with an “organic ethos”—understood as producers’ commitment to core organic principles and the organic movement. The paper highlights producers’ values as perceptual filters and cognitive mechanisms that help shape producers’ policy impacts perceptions, illustrating a contributing factor to the enduring nature of organic policy debates. 相似文献
50.
Jennifer A. Kagan 《政策研究评论》2019,36(2):217-241
Renewable portfolio standards (RPS) are an important policy tool for reducing carbon emissions and advancing the global shift toward renewable energy. As the U.S. federal government backs away from commitments to reduce greenhouse gas emissions, subnational governments play an increasingly important role in mitigating climate change. In June 2015, Hawaii became the first state in the United States to adopt a 100% RPS. Through understanding the conditions that gave rise to Hawaii’s RPS, policy actors will be better informed as they navigate policy processes in other states and jurisdictions. This study uses Kingdon’s Multiple Streams Framework (MSF) to explore the policy process that led to Hawaii’s 100% RPS. Data were collected during the summer of 2016 via interviews with 25 key policy actors and informants in Hawaii. Expectations based on the MSF are confirmed, and the results suggest factors that might be included or explored in future studies of RPS adoption. 相似文献