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11.
对天津及其滨海新区生态城市水利建设进行了分析。研究了在淡水资源极度匮乏的条件下,有效开发利用非常规水资源的必要性、重要性和现实性。认为天津市对水资源应遵循节水、治污、高效配置,妥善处理生活、生产、生态之间的关系,力求平衡调配。供水水源应是多元的,增加非常规水资源(污水、海/咸水、雨/洪水)的利用,同时增加可用地下水,外调来水等,逐步进入可持续发展配置。 相似文献
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Twenty-one 15- to 17-year-olds attempted to purchase cigarettes in 232 stores in the manner that confederates typically do in access studies, as well as in the manipulative ways (e.g., lying about their ages) that youth smokers do, thereby modeling youth access to tobacco within versus outside of studies, respectively. Youth typical-research versus manipulative behavior was contrasted with clerk behavior (requests for youth ID cards) to examine the relative contributions of both to youth access to tobacco for the 1st time. Results revealed that clerk behavior was the strongest predictor of cigarette sales to youth and hence underscore the need for interventions with merchants. Sales nonetheless were higher under youth-manipulative conditions and thereby highlight the low ecological validity of access research. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Rowan Paul J.; Cofta-Woerpel Ludmila; Mazas Carlos A.; Vidrine Jennifer Irvin; Reitzel Lorraine R.; Cinciripini Paul M.; Wetter David W. 《Canadian Metallurgical Quarterly》2007,15(4):382
Ecological momentary assessment (EMA) consists of assessing phenomena in real time in the natural environment. EMA allows for more fine-grained analyses of addictive behavior and minimizes threats to internal validity, such as recall biases and errors. However, because of the intensive monitoring involved in EMA, measurement reactivity is a concern. To test whether EMA with palmtop personal computers induces reactivity, the authors compared smoking-related outcomes between smokers using EMA and those not using EMA during a quit attempt. The use of no-EMA control groups has been rare in reactivity investigations to date. The EMA protocol included event-contingent assessments (smoking episodes, urge episodes) and random assessments. Outcomes included biologically confirmed abstinence and self-report measures of withdrawal, self-efficacy, motivation, affect, and temptations. Participants were smokers motivated to quit (N = 96). They were randomized to 1 of 3 groups: EMA for the week preceding a planned quit date, EMA for the week following the quit date, and no EMA. Abstinence rates did not differ between the groups at Day 7 or at Day 28 postcessation. For the 20 subscales assessed at each of 3 assessment times, there were significant differences between participants with and without EMA experience for 3 subscales at the 1st of 3 assessment times, and significant differences for 3 different subscales at the 3rd assessment time. These differences suggest some reactivity to EMA, although the inconsistent pattern across time indicates that further research is needed to definitively conclude that EMA induces reactivity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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河北省迁安市滦河生态防洪工程是河北省重点工程建设项目,在建设中采用土工格室生态护岸工程技术,不仅大大提高了工程建设的速度和质量,而且延长了堤坝使用寿命,减少了维护成本,收到了环保、生态等方面的综合效益。 相似文献
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Processes affecting fish populations range in scale from local to global. Fish response is also scale‐dependent, with some activities varying locally while others depend on large‐scale connectivity within or between watersheds. These issues are still only partly recognized, with large‐scale research often affected by non‐independent sampling, weak inference, poor model testing or model over‐extrapolation. Available multi‐scale studies can reach different conclusions about factors affecting fishes from local studies, but results vary between examples. Potential explanations are (i) effects on fishes are context‐dependent; (ii) different species or life‐stages are limited in different ways; (iii) multi‐scale studies are too few for generalization. We advocate improved use of geostatistical tools to guide sampling or interpret the spatial extent of management problems, and we illustrate this using brown trout in Welsh streams. Our strongest recommendation is that fish ecologists recognize the importance of interactions across scales in quantifying effects on fishes so that management decisions can be better based on evidence rather than judgement or extrapolation. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
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浅析南水北调工程对河北省受水区生态环境的影响 总被引:1,自引:0,他引:1
南水北调工程的实施将缓解河北省长期缺水的严重局面,对其生态环境产生显著影响。该文从社会经济、气候环境、水环境、土壤、地质环境以及水生生物等多个层面分析了南水北调工程对河北省受水区生态环境的影响,为合理利用来水,保护和改善河北省生态环境及促进河北经济的持续稳定发展提供依据。 相似文献
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为了解决普遍采用单方水资源价值计算河道生态基流价值的缺陷,以及探索河道生态基流价值定量化计算新方法,采用水力学方法将河道生态基流从径流量中分离出来,并确定河道生态基流对应水面面积,进而采用当量因子法计算河道生态基流价值和并探索分析了河道生态基流价值的时间变化特征。以渭河干流宝鸡段为例进行研究,结果表明:渭河干流宝鸡段的丰水年、平水年以及枯水年的年平均河道生态基流量分别为5.82 m~3/s、3.59 m~3/s和2.76 m~3/s。近21 a来,该段河道生态基流价值在时间上总体呈下降趋势,该价值多年平均值为5.61亿元,单方河道生态基流价值为6.27元/m~3,单方价值与价值总量变化趋势相反。河道生态基流价值年内变化具有明显的周期性,总体呈倒"V"字型,汛期河道生态基流价值比非汛期大,单方河道生态基流价值与之相反。通过相同区域以及相近区域的河道生态基流价值研究成果以及价值变化特征的对比分析,证明研究成果较为合理。该方法可为河道生态基流合理保障提供定量化依据。 相似文献