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271.
中国正处于巨大的社会变迁之中,复杂性与不确定性的环境特征对政府能力提出了更高要求。从系统论的视角看,政府能力体现在政府对变迁中社会环境的反应、适应与变革能力。基于系统论的政策学解读,政府能力最终可以归为“制定”和“执行”公共政策的能力。从环境与组织管理的关系出发,围绕公共政策的生命过程,可以分别考察政府在输入、转化、输出三个环节中政策制定和政策执行的情况,进而探讨政府能力提升的路径。  相似文献   
272.
近代城市人口的增长、城市职能的变化、市政机构的出现带来了城市空间的转变。20世纪初,中国开始了大范围的城市基础设施改造与新建。其中最有代表性的是拆城、填濠、修筑环城马路的工程,此后全国大部分的城市改造都遵循了相似的模式。本文通过对近1200座治所城市城墙变动信息的研究发现,20世纪大规模的城市空间改造最初主要从东南沿海省份开始,30年代末至40年代的战争打破了这一过程,但随着新中国成立后城市建设的恢复,空间改造的进程继续向西部省份推进,总体上呈现由东向西,由中心向边缘发展的特点。  相似文献   
273.
What is the influence on reference price when the source of price information is anonymous versus social? This article investigates the formation of reference prices given an observed sequence of past prices in a service context. An experimental study suggests that, considering the same price information, if the source is social (i.e., the prices paid by colleagues), then consumers want to pay less. More specifically, social comparison changes the way individuals weigh information, attributing more importance to the lowest historical prices and to the range in price variations.  相似文献   
274.
This study examined the effect of Testofen, a specialised Trigonella foenum-graecum seed extract on the symptoms of possible androgen deficiency, sexual function and serum androgen concentrations in healthy aging males. This was a double-blind, randomised, placebo-controlled trial involving 120 healthy men aged between 43 and 70 years of age. The active treatment was standardised Trigonella foenum-graecum seed extract at a dose of 600?mg/day for 12 weeks. The primary outcome measure was the change in the Aging Male Symptom questionnaire (AMS), a measure of possible androgen deficiency symptoms; secondary outcome measures were sexual function and serum testosterone. There was a significant decrease in AMS score over time and between the active and placebo groups. Sexual function improved, including number of morning erections and frequency of sexual activity. Both total serum testosterone and free testosterone increased compared to placebo after 12 weeks of active treatment. Trigonella foenum-graecum seed extract is a safe and effective treatment for reducing symptoms of possible androgen deficiency, improves sexual function and increases serum testosterone in healthy middle-aged and older men.  相似文献   
275.
Understanding how wood develops has become an important problematic of plant sciences. However, studying wood formation requires the acquisition of count data difficult to interpret. Here, the annual wood formation dynamics of a conifer tree species were modeled using generalized linear and additive models (GLM and GAM); GAM for location, scale, and shape (GAMLSS); a discrete semiparametric kernel regression for count data. The performance of models is evaluated using bootstrap methods. GLM was useful to describe the wood formation general pattern but had a lack of fitting, while GAM, GAMLSS, and kernel regression had a higher sensibility to short-term variations.  相似文献   
276.
This paper considers quantile regression for a wide class of time series models including autoregressive and moving average (ARMA) models with asymmetric generalized autoregressive conditional heteroscedasticity errors. The classical mean‐variance models are reinterpreted as conditional location‐scale models so that the quantile regression method can be naturally geared into the considered models. The consistency and asymptotic normality of the quantile regression estimator is established in location‐scale time series models under mild conditions. In the application of this result to ARMA‐generalized autoregressive conditional heteroscedasticity models, more primitive conditions are deduced to obtain the asymptotic properties. For illustration, a simulation study and a real data analysis are provided.  相似文献   
277.
For many continuous distributions, a closed-form expression for their quantiles does not exist. Numerical approximations for their quantiles are developed on a distribution-by-distribution basis. This work develops a general approximation for quantiles using the Taylor expansion. Our method only requires that the distribution has a continuous probability density function and its derivatives can be derived to a certain order (usually 3 or 4). We demonstrate our unified approach by approximating the quantiles of the normal, exponential, and chi-square distributions. The approximation works well for these distributions.  相似文献   
278.
The main purpose of dose‐escalation trials is to identify the dose(s) that is/are safe and efficacious for further investigations in later studies. In this paper, we introduce dose‐escalation designs that incorporate both the dose‐limiting events and dose‐limiting toxicities (DLTs) and indicative responses of efficacy into the procedure. A flexible nonparametric model is used for modelling the continuous efficacy responses while a logistic model is used for the binary DLTs. Escalation decisions are based on the combination of the probabilities of DLTs and expected efficacy through a gain function. On the basis of this setup, we then introduce 2 types of Bayesian adaptive dose‐escalation strategies. The first type of procedures, called “single objective,” aims to identify and recommend a single dose, either the maximum tolerated dose, the highest dose that is considered as safe, or the optimal dose, a safe dose that gives optimum benefit risk. The second type, called “dual objective,” aims to jointly estimate both the maximum tolerated dose and the optimal dose accurately. The recommended doses obtained under these dose‐escalation procedures provide information about the safety and efficacy profile of the novel drug to facilitate later studies. We evaluate different strategies via simulations based on an example constructed from a real trial on patients with type 2 diabetes, and the use of stopping rules is assessed. We find that the nonparametric model estimates the efficacy responses well for different underlying true shapes. The dual‐objective designs give better results in terms of identifying the 2 real target doses compared to the single‐objective designs.  相似文献   
279.
以全国221个村庄所获得的4年调查数据作为研究基础,对"家电下乡"政策的消费效应予以评估和分析。调查表明,家电下乡政策消费效应的最大特征是农民消费需求的释放,其中包括全国消费总额的上升,户均消费额增幅达到8成,全国各地消费总量和户均消费数量的增加。但家电下乡政策的消费效应在实践中也遇到了持续性疲软的难题,如农民收入的限制作用,农民购买下乡产品比重偏低,政府补贴额和补贴程序不足,政策宣传和解说不到位。为了使家电下乡政策的消费效应持续起效,必须不断完善政策,使家电下乡政策的实惠真正落实到农民身上。  相似文献   
280.
郭渊 《太平洋学报》2011,19(5):83-92
20世纪六七十年代,美、前苏联出于争夺世界霸权的需要,对南海争端采取了不同的政策,南海地区"边缘地带"特性进一步凸显。在此背景下,菲律宾、越南和马来西亚等国强占南海岛礁、瓜分海域、掠夺资源。在维权斗争中,中国政府不断地进行南海诸岛主权宣示,抗议周边国家对中国海洋国土主权的践踏,收复被占西沙岛礁,并采取切实措施加强海疆国防建设。  相似文献   
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