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1.
如何营造舒适的微气候环境,激发市民休闲体力活动意愿,成为提高寒地城市公园公共健康效能的重要课题。在探讨休闲体力活动水平与微气候热舒适关联性、关联特征基础上,利用线性回归揭示各因子关联机理,并结合散点图划定微气候因子适宜值区间。研究结果表明:1)休闲体力活动时长、代谢量与热舒适呈线性关联,活动人次及强度类型与热舒适呈时段性、滞后性和非线性关联;2)非舒适的微气候环境下,主观意愿及社交需求提高活动主体7.5℃的对抗强度;3)太阳辐射、风速与休闲体力活动水平存在显著关联机理;4)低温、通风的微气候特征可有效增加低、中等强度活动人次,延长活动时长,低风、低湿、高日照有利于诱发中等以上强度活动发生,旨在为营造微气候适宜性的休闲体力活动空间提供数据支持,推动“健康中国”国策的实施。  相似文献   

2.
城市绿色基础设施的建设对于城市热环境改善及绿色高质量发展具有显著作用。借助CiteSpace软件对2000—2020年Web of Science核心数据库检索出的270篇城市绿色空间热舒适性分析相关文献进行研究进展与趋势的梳理。结果表明:(1)城市绿色基础设施热舒适性研究具有明显的三段式发展过程,学科属性差异使得国内外形成多个较为独立的核心团队,研究呈现较强地缘性;(2)研究热点紧随国际时势变化呈现主题多样性、多学科参与、多尺度效应,关注点由绿色基础设施热效应缓解特征—热舒适性评价方法及微气候效应特征—顾及居民高质量生活方式与健康的热舒适影响研究逐渐发展变化;(3)研究价值诉求逐步转向居民,利用技术与学科交叉实现多元融合的绿色基础设施热舒适性改善策略研究将成为重点。  相似文献   

3.
在全球气候变暖和中国城市存量发展的背景下, 倡导气候适应性的城市公园设计,成为缓解城市热岛效应的 重要手段之一。从公园的降温范围和降温幅度2个方面,提 出并定义了城市公园降温效益的测度指标,量化其对城市温 度的调节能力,进而探讨有关公园设计要素对公园降温的影 响。研究发现:1)城市公园能够在90m范围内产生显著的 降温作用,最大降温范围可达500m;2)城市公园降温效益 除了受到自身要素影响外,还会受到周边所处建成环境的影 响;3)公园设计要素中面积大小、边界形态、植被覆盖度、 地形变化、蓝绿空间面积比5个要素对其降温效益的发挥产生 影响,且影响多为非线性;4)将降温影响要素的认知用于理 想情景模拟,发现高温热点区域的面积减少超过50%。研究 进一步加深了对城市公园降温效益的认识,为气候适应性的 公园设计在调节城市温度方面提供参考。  相似文献   

4.
声音作为景观要素越来越受到重视,人们对声环境的感知受到声音本身特性以及声音与环境交互作用的共同影响。以天津水上公园为研究对象,将声音的响度、频率和多样性指数作为公园声音元素的特征指标,定量研究声音构成、景观要素和舒适度三者之间的相关关系。结果表明:水上公园的声音多样性指数(SDI)整体较高,声音类型丰富,但不同的景观要素对应的声音特征不显著;听觉舒适度与整体舒适度呈极显著正相关;听觉舒适度主要受到人类活动声和机械声的影响,其出现频率(POS)和响度(PLS)均干扰了被试者对自然声的感知。针对公园的景观格局、声环境现状及使用者需求,提出声环境的设计和管理优化策略,对改善公园声景观品质、提高公园整体的环境舒适度具有重要意义。  相似文献   

5.
城市街道空间是城市重要的户外公共生活空间。由 行道树和街谷构成的林荫街谷空间对改善街道空间微气候和 调控冬夏两季热舒适环境起着重要作用。通过对西安2组城市 “单拱”型林荫街谷空间进行冬季微气候实态测试,分析归纳 林荫街谷冬季动态热环境的气温变化特征,将“相对热舒适” 区域划分为“冷区”(不舒适区)、“暖区”(舒适区)、“日 晒区”(愉悦区),并建立2种热环境动态变化模式,同时基于 人体热健康“动态热适应”原理,提出冬季面向健康热环境的 街道空间调控策略,对以西安为代表的建筑气候区划中的寒冷 地区街道空间气候适应性设计提供了一定的参考价值。  相似文献   

6.
增加植被绿化是调节城市微气候和改善城市热岛效应的主要策略之一。然而,对竹类植物群落的微气候特征和热舒适度调节却鲜有研究。以杭州11种常见竹类植物为研究对象,分析了不同竹类植物群落的微气候变化特征,并采用不舒适指数来评价不同竹类植物群落对人体热舒适度的影响。结果显示,不同竹类植物群落与对照点相比,其空气温度、相对湿度以及光照强度存在显著差异。与对照点相比,乔木状竹类植物群落能够降低空气温度1.5~2.6℃,增加相对湿度3.0%~7.9%,遮光率达95.4%~99.9%。不同竹类植物群落与对照点相比,其平均不舒适指数的差异表现为极显著。与对照点相比,乔木状竹类植物不舒适指数降低2.1%~3.5%。通过对微气候因子与竹类植物群落冠层结构特征之间的相关性分析表明,冠层结构特征对植物群落微气候和不舒适指数起着重要的调节作用。本次研究可以提供更多关于竹类植物缓解热岛效应的基础知识,有助于在风景园林规划设计中合理选择竹类植物种类,从而改善城市热环境。  相似文献   

7.
四川盆地边缘乡村生态旅游景观规划研究   总被引:1,自引:0,他引:1  
生态旅游带来的社会效益、生态效益和经济效益无需赘述.文章采用田野调查和案例分析的研究方法,以四川省董坪村为实证研究,从农业生态景观、雨水收集利用景观和户外微气候改善景观三方面探讨山地乡村生态旅游景观规划.规划研究在实际建设中取得了初步成效.尽管规划建设成效还不十分明显而需要时间证明,但结合当地植物、水、道路和住宅等景观要素,规划乡村生态旅游景观是相对简单和低成本的有效方法和策略,并可逐步实现不误农时、不废农景、改善户外微气候、节能减排的规划目标.  相似文献   

8.
随着乡村旅游的迅速发展,乡村景观的游憩价值日益受到人们的关注。从乡村游憩产生的动机和特征入手,寻找乡村人居环境“背景元”“活动元”“建设元”有机联系、三元互动的关系,分析由背景元主导的乡村游憩资源的构成要素及功能特征。以优美性、乡土性、宜游性为价值标准,建立乡村景观游憩价值评价的指标体系,提出乡村景观游憩价值的核心,坚持和传承乡村人居环境背景的整体保护、乡村人居活动的活化、乡村人居建设因地制宜的传统,保护乡村人居环境的自然度、丰富度、和谐度;突出乡村文化的地域性、原真性、传承性;优化乡村建设的清洁度、舒适度和可达度。从而以游憩价值的发掘和利用为契机、实现乡村景观价值的保护、彰显和提升,以游憩为推动力,促进乡村人居环境的改善提质。  相似文献   

9.
为应对快速城镇化过程中愈发严重的热岛效应,如 何针对面积有限的绿地进行空间配置特征优化,使其降温效率 最大化,亟待深入探究。以高分2号遥感影像为数据源提取长 春市城市绿色空间分布格局,引入景观参数研究其分布情况; 利用劈窗算法获取地表温度,研究城市绿地的降温效率及其 影响因素,结果表明:1)0.5≤S<1hm2 的绿地,增加植被 覆盖率能够显著提升其降温效率;1≤S<5hm2 的绿地,增加 绿地面积或植被覆盖率能够提升其降温效率;5≤S<10hm2 的绿地,紧凑、点状的绿地的降温效率优于线状绿地; S≥10hm2 的绿地,其降温效果不再随面积增大而提升。2)城 市绿地面积越大,降温范围越大,但是二者的相关性不明显, 通常绿地的降温范围为150~400m。研究结果可以指导城市 绿地布局、形状、大小等配置特征的优化,使其降温效率最大 化,以达到降低温度、减缓城市热岛效应的目的。  相似文献   

10.
中国传统古镇特有的空间布局及构成与其局部环境 小气候有着直接的关联。为探究古镇环境小气候与空间特征之 关系,以嵩口为例,选取包含嵩口的滨水景观、宗祠庭院、古 镇街巷、古厝民居等代表性景观的2条主要游览路径,对路径 上不同空间特征景观节点的空气温度、相对湿度、风速等小气 候要素进行数据测量与搜集,计算其人体舒适度指数,并进行 对比、分析,以此探索古镇环境小气候影响的环境物理规律。 结果表明:环镇大樟溪对局部环境具有明显降温、增湿作用, 溪步道通风情况优于坡面及人工驳岸;建筑遮阴、街巷尺度、 朝向、植被与材质运用是影响街巷小气候的空间要素;而空间 开敞程度和植被造成的太阳辐射差异对庭院及小广场的小气候 环境影响较大。  相似文献   

11.
John Stuart Mill has traditionally been portrayed as self-contradictory and failing to construct a unified social theory. Recent scholarship, however, has challenged this view, finding Mill's work to be creatively synthetic in bridging the antinomies inherent in liberal democratic thought. This revisionist interpretation of Mill is advanced by an understanding of his theory of justice and its role in shaping his policy positions on issues such as welfare, education, voting rights, property rights, taxation, government intervention, and the future of capitalism.  相似文献   

12.
Arik Hesseldahl In the aftermath of the September 11 attacks, U.S. officials quickly turned their attention to other potential targets, including California's Golden Gate Bridge. What would happen if terrorists took down the bridge between San Francisco and Marin County? How much of the region would be affected and for how long?  相似文献   

13.
This article seeks to evaluate the appropriateness of a variety of existing forecasting techniques (17 methods) at providing accurate and statistically significant forecasts for gold price. We report the results from the nine most competitive techniques. Special consideration is given to the ability of these techniques to provide forecasts which outperforms the random walk (RW) as we noticed that certain multivariate models (which included prices of silver, platinum, palladium and rhodium, besides gold) were also unable to outperform the RW in this case. Interestingly, the results show that none of the forecasting techniques are able to outperform the RW at horizons of 1 and 9 steps ahead, and on average, the exponential smoothing model is seen providing the best forecasts in terms of the lowest root mean squared error over the 24-month forecasting horizons. Moreover, we find that the univariate models used in this article are able to outperform the Bayesian autoregression and Bayesian vector autoregressive models, with exponential smoothing reporting statistically significant results in comparison with the former models, and classical autoregressive and the vector autoregressive models in most cases.  相似文献   

14.
Abstract

The purpose of this paper is to introduce explicitly pleasure and belief in what aims at being a Humean theory of decision, like the one developed in Diaye and Lapidus (2005a). Although we support the idea that Hume was in some way a hedonist – evidently different from Bentham's or Jevons' way – we lay emphasis less on continuity than on the specific kind of hedonism encountered in Hume's writings (chiefly the Treatise, the second Enquiry, the Dissertation, or some of his Essays). Such hedonism clearly contrasts to its standard modern inheritance, expressed by the relation between preferences and utility.

The reason for such a difference with the usual approach lies in the mental process that Hume puts to the fore in order to explain the way pleasure determines desires and volition. Whereas pleasure is primarily, in Hume's words, an impression of sensation, it takes place in the birth of passions as reflecting an idea of pleasure, whose “force and vivacity” is precisely a “belief”, transferred to the direct passions of desire or volition that come immediately before action. As a result, from a Humean point of view, “belief” deals with decision under risk or uncertainty, as well as with intertemporal decision and indiscrimination problems.

The latter are explored within a formal framework, and it is shown that the relation of pleasure is transformed by belief into a non-empty class of relations of desire, among which at least one is a preorder.  相似文献   

15.
中国拥有世界五分之一强的人口 ,收入又在迅速增长。因此 ,国际上很自然地会考虑或推测她在今后的几十年是否有能力养活自己。中国的人口预计将从 2 0 0 0年的 1 2 8亿增长到 2 0 2 0年的 1 4 6亿 ,和 2 0 3 0年的 1 4 9亿。与此同时 ,人均收入的增长将导致对家畜和鱼类产品更大的需求 ,因而对饲料的需求也将有很大的增长  相似文献   

16.
In principle, we want regulatory programs to be based on current realities, as reflected for example in the best knowledge of relevant experts. That would imply that old rules now on the books should be consistent with today's knowledge base, not just what was known when a rule or standard was originally set. This paper reports on a survey of US programs, examining how often existing rules are actually updated in light of better knowledge, and identifies five programs that attempt to make policy routinely adaptive. These programs exhibit what we term Planned Adaptation: they both revise rules when relevant new knowledge appears, and take steps to produce such improved knowledge. While Planned Adaptation is rare, it is used in several nationally prominent programs, including air pollution, airplane safety, and drug safety. Planned Adaptation is a policy tool that deserves more attention.  相似文献   

17.
Synopsis Classification is an important activity that facilitates theory development in many academic disciplines. Scholars in fields such as organizational science, management science and economics and have long recognized that classification offers an approach for ordering and understanding the diversity of organizational taxa (groups of one or more similar organizational entities). However, even the most prominent organizational classifications have limited utility, as they tend to be shaped by a specific research bias, inadequate units of analysis and a standard neoclassical economic view that does not naturally accommodate the disequilibrium dynamics of modern competition. The result is a relatively large number of individual and unconnected organizational classifications, which tend to ignore the processes of change responsible for organizational diversity. Collectively they fail to provide any sort of universal system for ordering, compiling and presenting knowledge on organizational diversity. This paper has two purposes. First, it reviews the general status of the major theoretical approaches to biological and organizational classification and compares the methods and resulting classifications derived from each approach. Definitions of key terms and a discussion on the three principal schools of biological classification (evolutionary systematics, phenetics and cladistics) are included in this review. Second, this paper aims to encourage critical thinking and debate about the use of the cladistic classification approach for inferring and representing the historical relationships underpinning organizational diversity. This involves examining the feasibility of applying the logic of common ancestry to populations of organizations. Consequently, this paper is exploratory and preparatory in style, with illustrations and assertions concerning the study and classification of organizational diversity.  相似文献   

18.
The buildup of so-called greenhouse gases in the atmosphere — CO2 in particular-appears to be having an adverse impact on the global climate. This paper briefly reviews current expectations with regard to physical and biological effects, their potential costs to society, and likely costs of abatement. For a worst case scenario it is impossible to assess, in economic terms, the full range of possible non-linear synergistic effects. In the most favorable (although not necessarily likely) case (of slow-paced climate change), however, it seems likely that the impacts are within the affordable range, at least in the industrialized countries of the world. In the third world the notion of affordability is of doubtful relevance, making the problem of quantitative evaluation almost impossible. We tentatively assess the lower limit of quantifiable climate-induced damages at $30 to $35 per ton of CO2 equivalent, worldwide, with the major damages being concentrated in regions most adversely affected by sea-level rise. The non-quantifiable environmental damages are also significant and should by no means be disregarded.The costs and benefits of (1) reducing CFC use and (2) reducing fossil fuel consumption, as a means of abatement, are considered in some detail. This strategy has remarkably high indirect benefits in terms of reduced air pollution damage and even direct cost savings to consumers. The indirect benefits of reduced air pollution and its associated health and environmental effects from fossil-fuel combustion in the industrialized countries range from $20 to $60 per ton of CO2 eliminated. In addition, there is good evidence that modest (e.g. 25%) reductions in CO2 emissions may be achievable by the U.S. (and, by implication, for other countries) by a combination of increased energy efficiency and restructuring that would permit simultaneous direct economic benefits (savings) to energy consumers of the order of $50 per ton of CO2 saved. A higher level of overall emissions reduction — possibly approaching 50% — could probably be achieved, at little or not net cost, by taking advantage of these savings.We suggest the use of taxes on fossil fuel extraction (or a carbon tax) as a reasonable way of inducing the structural changes that would be required to achieve significant reduction in energy use and CO2 emissions. To minimize the economic burden (and create a political constituency in support of the approach) we suggest the substitution of resource-based taxes in general for other types of taxes (on labor, income, real estate, or trade) that are now the main sources of government revenue. While it is conceded that it would be difficult to calculate the optimal tax on extractive resources, we do not think this is a necessary prerequisite to policy-making. In fact, we note that the existing tax system has never been optimized according to theoretical principles, and is far from optimal by any reasonable criteria.During the academic year 1989–90 Dr. Ayres was at the International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.During the summer of 1989 Mr. Walter was a member of the Young Scientists' Summer Program at IIASA.  相似文献   

19.
20.
Neoliberal political movements advocate privatization of public pension systems. Globalization imposes pressure on nations to conform to neoliberal policy views with respect to the design and structure of social insurance, including public pension systems. The paper begins with an investigation of the economic, ethical and ideological dimensions of the privatization debates in the U.S.; it argues that privatization advocates may be largely moved by ideology, since the other reasons advanced appear weak or unfounded. The second part discusses the history of Social Security, the purposes for its creation, and some of its economic effects. Differences between public and private pension systems are considered. A brief international comparison of some aspects of public pension system finance and benefit structures is presented. The final section considers the ethical, macroeconomic and distributional implications of privatization, prefunding and payroll tax funding, and argues for a pay as you go system financed with income taxes. In order to promote equity, economic security, community, and social cohesion, public pension systems should be universal in coverage. In order to reduce the inequality, income insecurity, and aged poverty generated by market economies, public pension systems ought to be progressive: benefit/contribution ratios should be inversely proportional to income, and progressive income taxes should finance the system. To promote economic growth, the systems should be financed on a pay-as-you-go basis, and should not be prefunded except for an emergency reserve. The fiscal policy recommendations partially depend upon the theory developed by Abba Lerner in the 1940s, and recently advanced by Wynne Godley and Randy Wray: Lerner's “principle of functional finance.”  相似文献   

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