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51.
52.
Juan Equiza-Goñi 《Applied economics letters》2019,26(11):919-926
In this paper, we investigate the impact of oil prices on both aggregate and industry US real stock returns over the period 1973–2017. The empirical analysis contributes to the related literature introducing a state-dependent oil price (high and low) and the local projections approach. Our main finding is that, depending on the nature of the shock and industry, the negative effects of oil price shocks become exacerbated -and the positive effects get moderated- if oil prices are already high. 相似文献
53.
Laura Raisa Miloş Benaissa Chidmi Marius Cristian Miloş 《Applied economics letters》2019,26(16):1369-1372
Although many industries have benefited from advances in data-driven technology, education is making small steps in capitalizing on the huge potential of data systems. Since 2005, the U.S. Federal Government has been making large grants to help states build statewide longitudinal data systems (SLDS) with the goal of improving programme and teacher evaluation and engage in data-driven decision-making. We analyse whether the introduction of SLDSs improved student performance, measured using test scores for math and reading tests for 4th and 8th graders, as well as high school graduation rates. We find no effects of SLDSs on student performance up to 10 years from implementation. However, we find suggestive evidence that these systems may have long-run effects, emphasizing the long-run nature of educational data collection and policy analysis. 相似文献
54.
《Journal of World Business》2020,55(6):101110
This study examines the effect of key internationalization contingencies on SME survival. We argue early internationalization increases the probability of firm failure, while international experience reduces it. However, the survival odds among international new ventures may be improved by their post-entry international expansion scope and speed, and by managers’ competencies. These internationalization facets provide firms with opportunities to develop and exploit their resources and capabilities, and thus enhance their survival chances. Drawing on a sample of 271 manufacturers followed between 2005 and 2014, we find results that provide support to most of our arguments, and hold theoretical and managerial relevance. 相似文献
55.
The goal of this research is to develop and validate a multi-dimensional scale measure of brand fidelity. This paper reports the rigorous process of scale development, through two separate studies involving 592 US consumers. Study 1 involves scale item generation, content validation and scale purification, while Study 2 involves a two-wave data collection method, evaluating the refined brand fidelity scale within a nomological network of relationships. The results demonstrate the 20-item brand fidelity scale to have strong construct validity as a first-order reflective, second-order formative scale. The findings suggest that if consumers engage in the behaviours/cognitions (as defined within the brand fidelity scale), then consumer/brand relationships are likely to be stable and predictable; are likely to endure the ravages of time; and, importantly, are likely to remain monogamous. For practitioners, the overall brand fidelity score can be used to track brand performance over time and for industry benchmarking purposes. Additionally, the measured brand fidelity dimensions provide specific direction upon which remedial marketing action can be implemented. 相似文献
56.
利用辐射源目标的频移动态特征进行盲分选时,针对已有的分选方法不能很好解决非合作接收数据非周期、间断、交叠的问题,提出了一种改进的逻辑回归分选算法,将信号分选转化为轨迹分类的问题来处理。首先,借鉴多目标航迹起始模型中的M/N逻辑法的框架,设计新的数据关联门限,以建立目标起始曲线;其次,采用最小二乘拟合方法替代卡尔曼滤波,设计新的外推规则,建立载频变化预测曲线;分析新的接收数据与预测曲线的关联性,不断迭代回归或形成新的分支,最后获得目标分选结果。仿真与实测试验表明,利用逻辑回归分选算法,对不同运动目标搭载的同频辐射源可进行自动分选,4个仿真目标与2个真实目标的分选正确率达到100%。同时,该方法拓展了辐射源目标盲分选中的动态频移特征应用,为辐射源个体识别提供了新的支持。 相似文献
57.
Social Impact Bonds (SIBs) have emerged in recent years as outcome‐based public‐private partnerships (PPP) for the delivery of welfare services, where the payment to the private operator is linked to the achievement of superior social impact. Since the traditional infrastructure‐based PPP approach seems to have failed to achieve higher level of efficiency and, above all, effectiveness, this paper discusses the extent to which the SIB model can represent a reference point to innovate the PPP model by introducing more focus on outcome achievement and social value generation. 相似文献
58.
为研究石家庄市在"利剑斩污"行动管控期和非管控期挥发性有机物(VOCs)的污染特性变化,在2个时间段内对石家庄市3个国控点进行采样分析。通过苏玛罐(SUMMA罐)进行样品采集,利用气相色谱/质谱联用(GC/MS)仪对石家庄市区3个国控点的VOCs进行定性定量检测分析。结果表明,监测期间主要的特征污染物是二氯甲烷、二氯丙烷、苯和甲苯。与非管控期间相比,管控期间各污染物的质量浓度均有所降低,总VOCs平均质量浓度降低45.107μg/m~3,二氯甲烷质量浓度降低8.796μg/m~3,二氯丙烷质量浓度降低3.750μg/m~3,苯质量浓度降低18.285μg/m~3,甲苯质量浓度降低16.895μg/m~3。大气环境调控策略的实施,有效降低了VOCs浓度,减少了空气污染程度,空气质量改善效果显著。"利剑斩污"行动期间采取的相关举措,对于制定常态化下VOCs的防治对策具有一定的参考价值。 相似文献
59.
应用双指耦合结构和枝节加载谐振器(Stub-loaded Resonator,SLR)实现了一款基于阶梯阻抗谐振器(Stepped Impedance Resonator,SIR)的滤波器。该滤波器具有3个通带,带外抑制较好,工作频段提高。通过调整阻抗比可调节第二、三通带的谐振频率;SLR结构能够增加通带数量;SLR结构和双指耦合结构均能改善滤波器的S参数。HFSS软件仿真表明,3个通带的中心频率分别为3.5 GHz、6.6 GHz、9.2 GHz,对应的分数带宽分别为5.7%、3%、2%,S11分别为-18 dB、-22 dB、-24 dB,通带内的S21分别为-1.8 dB、-1 dB、-1 dB。电路的测量结果与仿真结果较为吻合。该滤波器在5G通信的低频段具有应用前景。 相似文献
60.
Chompunoot Duangjan Haijun Wang 《Canadian Journal of Administrative Sciences / Revue Canadienne des Sciences de l\u0027Administration》2019,36(2):248-259
This research aims to understand the performance of purchasing social responsibility (PSR) through moderating effect of purchasing strategic integration. The results show that PSR directly influences purchasing performance, while the relationship between PSR and purchasing performance is partially mediated by organizational learning. Moreover, strategic integration negatively moderates the relationship between PSR and purchasing performance. This study suggests that the adoption of PSR affects the operations of both buyers and suppliers in a supply chain that further encourage organizational learning and increases purchasing efficiency. The results also show that organizations may realize this effect of PSR practices but may focus on other purchasing practices, which affects purchasing performance. Copyright © 2018 ASAC. Published by John Wiley & Sons, Ltd. 相似文献