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Many scholars study when climate change communication increases citizen engagement. Yet, past work has largely used public opinion-based measures of engagement to evaluate alternative frames. In this paper, we argue for a new approach to evaluation, which is premised on research on the policy-making process showing that space on the political agenda and, ultimately, policy change are more likely to arise in response to changes in both public opinion and collective political action. Thus, we argue that alternative frames should be evaluated based on their consequences for both. This is especially critical given that frames can have divergent effects on attitudes and behavior. Using a combination of field and survey experiments, we apply our approach to evaluate two frames related to climate change risks. We find that they heighten people’s concern about climate change yet decrease their rate of political action to express that concern. Our results suggest caution with regard to these frames in particular and that, more generally, frames that might seem advantageous when examining public opinion may not be when political behavior is analyzed.
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Levee effects upon flood levels: an empirical assessment 总被引：1，自引：0，他引：1
This study used stream gauge records to assess the impact of levees on flood levels, providing an empirical test of theoretical and model predictions of the effects on local flood response. Focusing upon a study area in Illinois and Iowa for which levee records were available, we identified 203 gauges with ≥ 50 years hydrological record, including 15 gauges where a levee was constructed during the period of record. At these sites, step‐change analysis utilizing regression residuals tested levee‐related stage changes and levels of significance and quantified the magnitudes of stage changes. Despite large differences in stream sizes, levee alignments, and degree of floodplain constriction, the post‐levee rating‐curve adjustments showed consistent signatures. For all the study sites, stages for below bankfull (non‐flood) conditions were unaffected by levee construction. For above bankfull (flood) conditions, stages at sites downstream of their associated levees also were statistically indistinguishable before versus after levee construction. However, at all sites upstream of levees or within leveed reaches, stages increased for above bankfull conditions. These increases were abrupt, statistically significant, and generally large in magnitude – ranging up to 2.3 m (Wabash River at Mt. Carmel, IL). Stage increases began when discharge increased above bankfull flow and generally increased in magnitude with discharge until the associated levee(s) were overtopped. Detailed site assessments and supplementary data available from some sites helped document the dominant mechanisms by which levees can increase flood levels. Levee construction reduces the area of the floodplain open to storage of flood waters and reduces the width of the floodplain open to conveyance of flood flow. Floodplain conveyance often is underestimated or ignored, but Acoustic Doppler Current Profiler (ADCP) measurements analysed here confirm previous studies that up to 70% or more of the total discharge during large floods (~3% chance flood) can move over the floodplain. Upstream of levees and levee‐related floodplain constriction, backwater effects reduce flow velocities relative to pre‐levee conditions and, thus, increase stages for a given discharge. The empirical results here confirm a variety of theoretical predictions of levee effects but suggest that many one‐dimensional model‐based predictions of levee‐related stage changes may underestimate actual levee impacts. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Reuben Lasker 《Marine pollution bulletin》1978,9(12):320-321
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Coral branches partially block the flow of water through the colony, creating an inner zone of reduced water exchange where hypoxic conditions can develop during the night. Previous studies have shown that this oxygen deficiency is alleviated by the fanning behavior of mutualistic damselfish that spend the night between the coral branches, constantly moving their fins. Our findings show that fin‐stroking frequency during fanning by the damselfish Dascyllus marginatus is moderately plastic, with lower frequency under higher oxygen concentration, and vice versa. The inter‐play between oxygen concentration and fin motion maintains nearly steady oxygen concentration between the coral branches during the night. 相似文献
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The designation of streets by number is one of the hallmarks of North American urbanism, yet very few studies have examined the geographies of street numbering in U.S. cities and towns. This article provides one of the first comprehensive, nationwide assessments of the spatial distribution of street numbering and lettering practices across the United States. Drawing on data collected from Google Maps, census records, state almanacs, and related sources, we analyze the proportion of incorporated places in all fifty U.S. states that have adopted some form of street numbering or lettering; the regional variation in the prevalence of alphanumerical systems of street designation and the relationships between the occurrence of street numbering, population size, and date of incorporation. In doing so, the broader aim of this study is to undertake the empirical groundwork needed to develop a more nuanced critical theory of the social production of calculable space. 相似文献
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Historical geographic information systems (GIS) scholarship has provided important insights into a broad spectrum of historical questions in recent years. This article contributes to the emerging field of historical GIS by employing map algebra and transect analysis to quantitatively assess topographical change resulting from rapid urban growth in New York City since the first quarter of the nineteenth century. These methodological techniques enable a systematic comparison of Manhattan's historical and contemporary topography through a spatial analysis of various topographic metrics, including the extent of positive and negative elevation change, shifts in elevation range, the percentage of geographic area that experienced elevation changes, and the estimated volume of Earth added to and removed from particular areas within the study site. The results indicate that there were more valleys filled than hills leveled on Manhattan's East Side, whereas the reverse was the case on the West Side. The West Side, however, experienced considerably more topographic changes than its eastern counterpart, in large part due to the former's more rugged terrain. Overall, the evidence suggests that although Manhattan's topography has been radically transformed in certain respects, the broader spatial pattern of topographic variation has remained largely constant. These findings, therefore, can be used to support competing narrative claims concerning the significance of the topographical transformations that resulted from the urbanization process in New York City. 相似文献
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This paper describes the ocean bottom unit and surface ship deck unit of a multi-microprocessor-based underwater acoustic telemetry system designed primarily to address the application of tidal data gathering during the course of a hydrographic survey. The problems of tidal data collection are highlighted and the objectives of the acoustic telemetry system are stated. A shallow-water environmental model is used to obtain accurate estimates of parameters such as propagation loss, band-level noise, frequency dispersion, and time dispersion. The environmental model in conjunction with in situ measurements dictates the guidelines used in the system design. A breakdown of the units into subsystems is given and each subsystem is described. The results of tests performed with the system on June 12 and 13, 1982, in the Bedford Basin, Dartmouth, Nova Scotia, are summarized. Finally, other potential applications of the system are mentioned. 相似文献
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Reuben H. Brooks Dr. 《GeoJournal》1982,6(2):121-128
Drought-stricken NE Brazil is studied in the context of four regional units: the semiarid lowlands of the interior sertão, which have the maximum precipitation fluctuations; the well-watered Cariri valley, which experiences harvest shortages during abnormally dry years; the coastal fringe, which suffers during years of widespread drought; and the highlands of Baturite, where dry spells are noticed only through an influx of migrants from low-lying and drought-stricken areas.Adjustment to drought is, in general, low; it depends on the degree of drought awareness, which is also quite low. Affluent individuals are more inclined to make adjustments to droughts, although the likelihood of their being affected is less than among poor individuals. Middleclass individuals are more inclined to react to threats of an impending drought than to act under actual drought conditions. If age is taken into consideration, middle-aged individuals show greater awareness of drought conditions and a higher propensity to making adjustments than aged or youthful populations. Women are less inclined to make adjustments than men, and married people less than singles. Large families, probably compelled by the constraints, are especially prone to undertake changes in living conditions when a drought strikes.In general, the choices provided by economic feasibility, the possibilities of mitigating drought effects through technological know-how, and the social input of marriage and family size are very important parameters in shaping the character of the adjustments to drought. 相似文献
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ABSTRACTIn recent decades, urban policymakers have increasingly embraced the selling of naming rights as a means of generating revenue to construct and maintain urban infrastructure. This practice of “toponymic commodification” first emerged with the commercialization of professional sports during the second half of the 20th century and has become an integral part of the policy toolkit of neoliberal urbanism more generally. As a result, the naming of everything from sports arenas to public transit stations has come to be viewed as a sponsorship opportunity, yet such naming rights initiatives have not gone uncontested. This special issue examines the political economy of urban place naming through a series of case studies that consider how the commodification of naming rights is transforming the cultural landscapes of contemporary cities. In this introductory article, we provide an overview of the geographies of toponymic commodification as an emerging research focus within the field of critical urban toponymies and propose several theoretical approaches that can enhance our understanding of the commodification of naming rights as an urban spatial practice. We then discuss the main contributions in this special issue and conclude by exploring potential directions for future research on the geographies of urban toponymic commodification. 相似文献