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21.
本文分析了依靠生态修复能力恢复生态的理论依据及实践依据,提出搞好水土资源调查、统一规划、加大水土保持监督执法力度、正确处理治理与预防保护的关系是生态自然恢复的重要保证措施。 相似文献
22.
Significance of international mergers and acquisition
Good for easing lack of domestic oil reserves
China oil production is under severe deficit due to insufficient resources. Annual average growth rate of crude oil consumption was 7.41%, but annual average growth rate of crude oil supply was only 1.95% in China in past 10 years. Oil supply could not meet demand of economic development. It is predicted that degree of China's dependence on foreign will be as high as 60% in 2015. 相似文献
Good for easing lack of domestic oil reserves
China oil production is under severe deficit due to insufficient resources. Annual average growth rate of crude oil consumption was 7.41%, but annual average growth rate of crude oil supply was only 1.95% in China in past 10 years. Oil supply could not meet demand of economic development. It is predicted that degree of China's dependence on foreign will be as high as 60% in 2015. 相似文献
23.
水是基础性的自然资源和战略性的经济资源,是生态环境的控制性要素.水资源的可持续利用,是经济社会可持续发展极为重要的保证,也是维护人类环境的极为重要的保证.长江流域地跨华东、华中、西南3大经济区,总面积约占国土总面积的20%,多年平均径流量约占全国总量的35%,人口占全国总数的34.5%,国内生产总值约占全国的35%,长江流域的可持续发展牵动着半壁河山.随着西部大开发与三峡工程的兴建,长江流域在我国经济建设中的地位更加重要.保护好长江水资源和长江流域的生态环境,不仅对于长江流域的经济社会发展有着重要的意义,而且随着南水北调工程的实施,也将对华北、京津地区乃至全国的经济社会发展产生重要的作用. 相似文献
24.
为识别生态环境缺水严重的区域,合理评价生态环境用水的配置效果,本文提出了一种新的流域生态环境需水与生态环境缺水快速评估方法。将流域的生态环境需水满足程度定义为,流域"实际生态环境用水"与流域在未受或少受人类活动干扰时的"自然状态条件下的生态环境用水"的接近程度。以土地利用资料为基础,运用层次分析法构建流域生态环境需水特征指标来表征流域生态环境用水的相对大小;借鉴水体生物快速评估法的思想,通过流域单元划分、参照单元选择、参照组构建、参照组匹配、观测值与期望值的比较计算等步骤,可以对不同级别流域的生态环境缺水问题进行深入分析,从而快速识别生态环境缺水严重区域、预测其生态环境缺水动态变化,并对生态环境用水配置效果进行评价。 相似文献
25.
26.
利用各种自然因素创造良好的地下空间环境 总被引:1,自引:0,他引:1
提出了为创造良好的地下空间环境,必须要利用各种自然因素:天然光线、外部景观、绿色植物及水体,并将其引入地下的设想;指出了它们对地下空间的生态环境所引起的积极作用,特别是对人的心理产生的良好影响,并探讨了这几种自然因素在地下空间中的运用手法。 相似文献
27.
Faulty inhibition is theorized to be a central feature in attention-deficit/hyperactivity disorder (ADHD), but it remains unclear whether inhibitory impairments encompass both motoric and attentional domains. Further, characterization of inhibitory deficits in adults with ADHD is needed. We experimentally assessed adults who met diagnostic criteria for ADHD and a subgroup who had partially remitted. Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) subtype effects were also examined. Motoric inhibition was assessed with the antisaccade task, and attentional inhibition was assessed with the attentional blink (AB) task. Antisaccade results replicated prior findings of extended latencies and increased anticipatory saccades in ADHD. Errors, however, appeared to be epiphenomenal to ADHD as they were absent when symptoms had partially remitted. Anticipatory saccades appeared as potential core problems that remained even when symptoms had improved. Differential response patterns were found for predominantly inattentive and combined subtypes, with the latter showing increasing anticipatory movements with increasing fixation time. In the AB task, ADHD groups committed more errors but showed no convincing evidence of an abnormal blink. These results demonstrate clear effects on motoric inhibition but not attentional inhibition in adults with ADHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
28.
Crowell Sheila E.; Beauchaine Theodore P.; Gatzke-Kopp Lisa; Sylvers Patrick; Mead Hilary; Chipman-Chacon Jane 《Canadian Metallurgical Quarterly》2006,115(1):174
Numerous studies have revealed autonomic underarousal in conduct-disordered adolescents and antisocial adults. It is unknown, however, whether similar autonomic markers are present in at-risk preschoolers. In this study, the authors compared autonomic profiles of 4- to 6-year-old children with attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD; n = 18) with those of age-matched controls (n = 20). Children with ADHD and ODD exhibited fewer electrodermal responses and lengthened cardiac preejection periods at baseline and during reward. Although group differences were not found in baseline respiratory sinus arrhythmia, heart rate changes among ADHD and ODD participants were mediated exclusively by parasympathetic withdrawal, with no independent sympathetic contribution. Heart rate changes among controls were mediated by both autonomic branches. These results suggest that at-risk preschoolers are autonomically similar to older externalizing children. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
29.
With the increasing deployment of real-time audio/video services over the Internet, provision of quality of service (QoS)
has attracted much attention. When the line rate of future networks upgrades to multi-terabits per second, if routers/switches
intend to deliver differentiated services through packet scheduling, the reduction of computational overhead and elimination
of bottleneck resulting from memory latency will both become important factors. In addition, the decrease of average queueing
delay and provision of small delays for short packets are two further critical factors influencing the delivery of better
QoS for real-time applications. The advanced waiting time priority (AWTP) is a timestamp-based packet scheduler which is enhanced
from the well-known WTP. Although AWTP considers the effect of packet size, the latency resulting from timestamp access and
a great quantity of computational overhead may result in bottlenecks for AWTP being deployed over high-speed links. Many existing
schedulers have the same problems. We propose a multi-level hierarchical dynamic deficit round-robin (MLHDDRR) scheduling
scheme which is enhanced from the existing dynamic deficit round-robin scheduler. The new scheme can resolve these issues
and efficiently provide relative differentiated services under a variety of load conditions. Besides, MLHDDRR can also protect
the highest priority traffic from significant performance degradation due to bursts of low-priority traffic. We compare the
performance of AWTP with the proposed scheme. Extensive simulation results and complexity analysis are presented to illustrate
the effectiveness and efficiency of MLHDDRR. 相似文献
30.
研究了带随机利率的双二项风险模型的破产问题,得到了终极破产概率的上界、描述破产严重程度的破产前盈余分布和破产赤字的联合分布的递推公式,进而得到了终极破产概率、破产前盈余和破产瞬时盈余满足的积分方程. 相似文献