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251.
Ignacio N Lobato Carlos Velasco 《Econometrica : journal of the Econometric Society》2007,75(2):575-589
In this article we introduce efficient Wald tests for testing the null hypothesis of the unit root against the alternative of the fractional unit root. In a local alternative framework, the proposed tests are locally asymptotically equivalent to the optimal Robinson Lagrange multiplier tests. Our results contrast with the tests for fractional unit roots, introduced by Dolado, Gonzalo, and Mayoral, which are inefficient. In the presence of short range serial correlation, we propose a simple and efficient two‐step test that avoids the estimation of a nonlinear regression model. In addition, the first‐order asymptotic properties of the proposed tests are not affected by the preestimation of short or long memory parameters. 相似文献
252.
以温室气体减排为主要立足点的气候变化问题在国内外已经引起了广泛而热烈的关注,相比之下,气候变化对环境的影响还未被给予足够的关注,更不用谈气候变化适应性对环境法律的影响和挑战。我国气候变化的相关法律政策是以减缓为导向的,有关适应气候变化的法律法规还很少。气候变化的不确定性、不可避免性、不可逆转性和空间时间上的广泛性,对环境政策与法律的假定基础、环境法律目的和现行环境管理体制等都带来了全新的挑战。当务之急在于弄清气候变化与传统环境问题的本质区别,气候变化问题纳入现行环境法律的可行性等。 相似文献
253.
254.
常国利 《辽宁工程技术大学学报(社会科学版)》2001,3(1):29-30
本文分析了当前我国居民消费倾向下降对投资乘数所产生的弱化作用 ,以及对扩张性财政政策的作用所产生的不利影响 ,并论述了产生这一问题的原因 ,提出了解决这一问题的对策。 相似文献
255.
投资乘数不大是制约积极财政政策发挥作用的重要因素。当前影响我国投资乘数增大的因素有投资结构不合理所造成的吸纳劳动力不足 ,人们的消费倾向低 ,腐败所造成的投入资金的流失 ,市场交易费用的过高 相似文献
256.
Theories proposing climate change apathy is explained by inadequate knowledge do not account for why many informed and concerned Americans fail to act. While correlations between knowledge, efficacy for climate change, and attitude to mitigation have been observed, few studies have examined efficacy for climate change as a mediator. This study aimed to investigate the influence of specific climate change knowledge on attitude to mitigation via efficacy beliefs. A cross-sectional survey of 205 US adults recruited from Amazon's Mechanical Turk assessed participants’ climate change knowledge, efficacy for climate change, and attitude to mitigation. Indirect effects of self-efficacy for climate change were observed in three mediation models, suggesting efficacy for climate change explains some of the relationship between specific climate change knowledge and attitude to mitigation. The findings suggest risk communication can motivate pro-environmental attitudes with interventions that deliver information about climate change and develop efficacy for mitigation behavior. 相似文献
257.
With the inexorable march of climate change, increased flooding is inevitable. Understanding the feedback between federal flood mitigation policies and the ways in which local governments build flood resilience is a significant gap in the literature. In particular, the effect that federal flood mitigation grants have on the intensity of local flood mitigation is nonexistent. This work measures flood risk mitigation by using the level of participation in FEMA's Community Rating System (CRS). Communities that participate in the CRS and undertake mitigation are awarded points; more points imply a higher level of participation. Since its inception in 1990, CRS communities have received considerably more federal pre-disaster flood mitigation grants compared to non-CRS communities. This study assesses the effect of federal pre-disaster flood mitigation grants on the level of participation in the CRS program. We use data on Hazard Mitigation Assistance programs and CRS participation data between 2010 and 2015. We link these data to flood risk and socioeconomic information. Our results indicate (i) federal pre-disaster flood mitigation grants do not appear to significantly influence the level of CRS participation, (ii) the effect of flood risk and socioeconomic factors on the level of CRS participation are mixed, and (iii) the current level of CRS participation is influenced by the previous level of CRS participation, which is not tied to federal pre-disaster flood mitigation grant. These findings add to the growing discussions on the drivers and barriers of local flood risk mitigation. 相似文献
258.
何吉欢 《上海理工大学学报(社会科学版)》1999,(2):127-130
应用拉氏乘子法消除Hellinger-Reissner变分原理的约束关系时,在识别拉氏乘子的过程中,会出现拉氏乘子为零的现象,这种现象称为临界变分现象,本文提出了一些新的观点来解释这种现象。 相似文献
259.
This study used two randomized experiments in a prospective design (Study 1 N = 297, Study 2 N = 296) to examine how multilevel causal attribution dimensions (internal vs. external to an individual or a country) shape domestic and foreign policy support to counter transboundary risk. Results from Study 1 and 2 showed that external-country (vs. internal-country) causal attribution reduced perceptions of internal-country attributions of responsibility, which had a cross-lagged effect on support for domestic-industry policies to mitigate the risk. In contrast, perceptions of external-country attributions of responsibility increased support for foreign policies in a 2-week follow up. This study offers theoretical insights into the demarcation of multilevel causal attribution dimensions in studying media framing effects. It also highlights some important causal mechanisms of how media frames shape public support for policies aimed at transboundary risk mitigation. 相似文献
260.
The 2020 hurricane season threatened millions of Americans concurrently grappling with COVID-19. Processes guiding individual-level mitigation for these conceptually distinct threats, one novel and chronic (COVID-19), the other familiar and episodic (hurricanes), are unknown. Theories of health protective behaviors suggest that inputs from external stimuli (e.g., traditional and social media) lead to threat processing, including perceived efficacy (self- and response) and perceived threat (susceptibility and severity), guiding mitigation behavior. We surveyed a representative sample of Florida and Texas residents (N = 1846) between April 14, 2020 and April 27, 2020; many had previous hurricane exposure; all were previously assessed between September 8, 2017 and September 11, 2017. Using preregistered analyses, two generalized structural equation models tested direct and indirect effects of media exposure (traditional media, social media) on self-reported (1) COVID-19 mitigation (handwashing, mask-wearing, social distancing) and (2) hurricane mitigation (preparation behaviors), as mediated through perceived efficacy (self- and response) and perceived threat (susceptibility and severity). Self-efficacy and response efficacy were associated with social distancing (p = .002), handwashing, mask-wearing, and hurricane preparation (ps < 0.001). Perceived susceptibility was positively associated with social distancing (p = 0.017) and hurricane preparation (p < 0.001). Perceived severity was positively associated with social distancing (p < 0.001). Traditional media exhibited indirect effects on COVID-19 mitigation through increased response efficacy (ps < 0.05), and to a lesser extent self-efficacy (p < 0.05), and on hurricane preparation through increased self-efficacy and response efficacy and perceived susceptibility (ps < 0.05). Social media did not exhibit indirect effects on COVID-19 or hurricane mitigation. Communications targeting efficacy and susceptibility may encourage mitigation behavior; research should explore how social media campaigns can more effectively target threat processing, guiding protective actions. 相似文献