近44 年关中夏季分级雨日及降水量的变化特征

[目的]通过对关中地区夏季雨日(量)进行分级研究,更深入地了解关中夏季降水变化特征及各级雨日(量)对关中夏季降水变化的贡献大小。[方法]利用1970~2013年关中地区44个气象站逐日降水资料,采用趋势分析法,Mann-Kendall检验,t-检验和GIS技术等方法对关中夏季不同等级雨日和雨量变化特征进行分析。[结果](1)关中多年平均夏季雨日空间分布均为西多东少,西北部塬区和山区丘陵多于平原,各等级雨日和对应雨量空间分布特征及变化趋势相似。(2)近44年关中夏季总雨日、小雨日(量)和大雨日(量)均呈减少趋势,夏季降雨总量、中雨日(量)和暴雨日(量)均呈增加趋势,但线性变化趋势均不显著。其中小雨日(量)和大雨日(量)分别在1989年和1985年发生突变性减少,中雨日(量)在1978年发生突变增加。(3)单站分析表明关中夏季总雨日除咸阳大部外多数呈负趋势,夏季降雨量除渭南大部外普遍为正趋势。其中大部分站点小雨日(量)和大雨日(量)为负趋势,减少显著的站点分布在宝鸡地区;中雨日(量)和暴雨日(量)普遍为正趋势。[结论]夏季总雨量的增加主要贡献者是中雨量增加,总雨日减少主要是小雨日减少引起。从长期趋势变化看,关中夏季降水强度有增加趋势。     

Online Survey Data Quality and Its Implication for Willingness‐to‐Pay: A Cross‐Country Comparison

Using online surveys to elicit consumer preference is gaining popularity because of several advantages offered by this method. Past research mainly focuses on the comparison between online surveys and other survey modes. Few have explored methods of using online survey tools to improve data quality for consumer willingness‐to‐pay (WTP) estimates. This article determines the impact of using a validation question (VQ) approach that asked survey respondents to select a particular answer on improving online survey data quality across six countries. Results show that survey data quality is a common problem in online surveys across countries and the severity of this problem differs significantly. Using VQs might detect the respondents who are less careful in answering survey questions, thus providing less reliable answers. The econometric models for respondents who correctly answer VQs (pass VQs) perform significantly better than the models for respondents who incorrectly answer VQs (fail VQs). The WTP estimates for respondents who pass and fail VQs differ significantly; and in general the WTP estimates for respondents passing VQs have smaller variances than those for all respondents and for respondents failing VQs.     

石油勘探开发科研工作的特点及科研定位

石油勘探开发的生产过程是一个探索的过程,因此其科研工作特点不同于制造业,除了Ｂ＆Ｄ（研究与开发）外,旨在维持正常生产过程的生产研究对于一个石油产往往更重要。一个石油公司的科研单位,首先要根据公司的要求和需要对自己的科研工作进行定位。我国石油公司的科研单位较普遍地存在定位不准确或定位不清楚的问题。在一定程序上影响了公司总体科研效率的提高。     

基于分类最优原理的小企业信用风险评价

基于分类最优原理进行小企业信用风险评价,即以违约样本和非违约样本的重心距离最大为目标函数,以指标的三角模糊熵及变异系数组成的指标权重区间为约束条件,确定指标的组合权重,评价小企业信用风险状况。应用实例结果表明:利用该方法评价小企业的信用风险,能够更好地区分违约客户与非违约客户,使模型的判别精度有所提高。     

关系强度与非对称性对宽恕意愿的影响

宽恕对提升组织绩效有积极作用.本文研究了关系强度与关系非对称性对宽恕意愿的影响,并探讨了行为的非道德强度对前述关系的调节作用.通过460个样本的2个组间情境实验发现:第一,关系强度正向影响宽恕意愿,关系强度越高,宽恕意愿越容易产生;第二,非对称性关系中,处于强势地位的一方,宽恕意愿更强;第三,非道德强度调节了关系非对称性对宽恕意愿的影响,在面对非道德强度低的场景时处于强势地位的一方其宽恕意愿更强,而面对非道德强度高的场景时处于弱势地位的一方其宽恕意愿更强.因此,团队管理者应致力于提升团队成员间的关系强度,并更多关注关系非对称性中处于弱势的一方.     

创新能力、空间依赖与长三角城市群增长核心演化

城市群经济系统发展过程中,核心城市的增长极化与扩散作用是推动城市群协同发展的关键机制。创新能力、要素集聚与扩散形成的区际空间外部性使得城市群增长核心不断演化,并形成系统协同发展的内在动力。长三角城市群核心城市的极化效应呈现出下降趋势,对其主要影响因素的实证分析结果表明：创新分工过程中创新要素集聚与创新溢出、空间依赖都对城市极化效应具有显著影响。因此,政策导向应从强化城市间创新分工、充分利用创新过程的空间外部性、推进城市群协同发展的制度创新等方面着手。     

中国交通基础设施建设改善了企业资源配置效率吗?——基于高速公路建设与制造业企业要素投入的分析

交通基础设施建设已被证实是改善发展中国家经济表现的重要因素,但其中的作用机制仍然众说纷纭.近年来,人们普遍认为资源在企业间的配置效率不同是国家间经济绩效差异的重要原因.为了验证交通基础设施是否确实影响了企业资源配置效率,进而提升了经济绩效,文章将中国制造业企业数据与高速公路建设数据进行匹配,并以此为基础对中国交通基础设施建设对企业资源配置效率的影响及其作用机制进行了实证分析.我们的研究发现:交通基础设施建设确实改善了企业的资源配置效率,距离高速公路更近的城市,企业的实际规模与最优规模差异更小.具体来看,交通基础设施降低了同时使得资本和劳动投入偏离的产出扭曲,使得企业的实际规模与最优规模更为接近.进一步的中介效应分析发现,高速公路影响企业资源配置效率的因素主要有价格加成和行业集中度等,而通过企业存货产生的作用并不显著.     

金融支持路径对风电产业技术创新影响的比较研究

寻找有效的金融支持路径对我国风电产业突破技术瓶颈具有重要意义。以风电产业为研究对象,建立协整与误差修正模型,分析金融支持与技术创新间的长期及短期均衡关系,在此基础上应用典型相关分析对金融支持与技术创新的具体关系进行讨论。研究表明：金融支持与技术创新间存在长期正向均衡关系,当技术创新水平偏离均衡状态时,误差修正项的反向修正机制可使其恢复到长期均衡;政府补贴对代表技术创新产出的专利数有正向推动作用,银行信贷额对研发支出和固定资产投入具有正向推动作用,股票市场对技术创新的作用不显著。     

Does high‐speed rail connection really promote local economy? Evidence from China’s Yangtze River Delta

High‐speed rail (HSR) has led to a transportation revolution in China. This paper uses the county‐level panel data of China’s Yangtze River Delta to investigate the effect of HSR connection on local economy. To address the issue of endogenous HSR route placement, we use a straight‐line strategy to construct potential HSR connection variables as instrumental variables of the actual HSR connection. Both the difference‐in‐differences and instrumental variable methods show that HSR connection impedes local economy, especially in peripheral regions. The impediment effect is channeled through population reallocation from peripheral to core areas and the restructuring of industries.     

Economic burden associated with inadequate antidepressant medication management among patients with depression and known cardiovascular diseases: insights from a United States–based retrospective claims database analysis

Abstract

Aims: The current study examined the association between insufficient major depressive disorder (MDD) care and healthcare resource use (HCRU) and costs among patients with prior myocardial infarction (MI) or stroke.

Methods: This was a retrospective study conducted using the MarketScan Claims Database (2010–2015). The date of the first MI/stroke diagnosis was defined as the cardiovascular disease (CVD) index date and the first date of a subsequent MDD diagnosis was the index MDD date. Adequacy of MDD care was assessed during the 90 days following the index MDD date (profiling period) using 2 measures: dosage adequacy (average fluoxetine equivalent dose of ≥20?mg/day for nonelderly and ≥10?mg/day for elderly patients) and duration adequacy (measured as the proportion of days covered of 80% or higher for all MDD drugs). Study outcomes included all-cause and CVD-related HCRU and costs which were determined from the end of the profiling period until the end of study follow-up. Propensity-score adjusted generalized linear models (GLMs) were used to compare patients receiving adequate versus inadequate MDD care in terms of study outcomes.

Results: Of 1,568 CVD patients who were treated for MDD, 937 (59.8%) were categorized as receiving inadequate MDD care. Results from the GLMs suggested that patients receiving inadequate MDD care had 14% more all-cause hospitalizations, 4% more all-cause outpatient visits, 17% more CVD-related outpatient visits, 13% more CVD-related emergency room (ER) visits, higher per patient per year CVD-related hospitalization costs ($21,485 vs. $17,756), higher all-cause outpatient costs ($2,820 vs. $2,055), and higher CVD-related outpatient costs ($520 vs. $434) compared to patients receiving adequate MDD care.

Limitations: Clinical information such as depression severity and frailty, which are potential predictors of adverse CVD outcomes, could not be ascertained using administrative claims data.

Conclusions: Among post-MI and post-stroke patients, inadequate MDD care was associated with a significantly higher economic burden.