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111.
The traditional estimation of higher order co-moments of non-normal random variables by the sample analog of the expectation faces a curse of dimensionality, as the number of parameters increases steeply when the dimension increases. Imposing a factor structure on the process solves this problem; however, it leads to the challenging task of selecting an appropriate factor model. This paper contributes by proposing a test that exploits the following feature: when the factor model is correctly specified, the higher order co-moments of the unexplained return variation are sparse. It recommends a general to specific approach for selecting the factor model by choosing the most parsimonious specification for which the sparsity assumption is satisfied. This approach uses a Wald or Gumbel test statistic for testing the joint statistical significance of the co-moments that are zero when the factor model is correctly specified. The asymptotic distribution of the test is derived. An extensive simulation study confirms the good finite sample properties of the approach. This paper illustrates the practical usefulness of factor selection on daily returns of random subsets of S&P 100 constituents. 相似文献
112.
Many research fields increasingly involve analyzing data of a complex structure. Models investigating the dependence of a response on a predictor have moved beyond the ordinary scalar-on-vector regression. We propose a regression model for a scalar response and a surface (or a bivariate function) predictor. The predictor has a random component and the regression model falls in the framework of linear random effects models. We estimate the model parameters via maximizing the log-likelihood with the ECME (Expectation/Conditional Maximization Either) algorithm. We use the approach to analyze a data set where the response is the neuroticism score and the predictor is the resting-state brain function image. In the simulations we tried, the approach has better performance than two other approaches, a functional principal component regression approach and a smooth scalar-on-image regression approach. 相似文献
113.
In this article, we propose a factor-adjusted multiple testing (FAT) procedure based on factor-adjusted p-values in a linear factor model involving some observable and unobservable factors, for the purpose of selecting skilled funds in empirical finance. The factor-adjusted p-values were obtained after extracting the latent common factors by the principal component method. Under some mild conditions, the false discovery proportion can be consistently estimated even if the idiosyncratic errors are allowed to be weakly correlated across units. Furthermore, by appropriately setting a sequence of threshold values approaching zero, the proposed FAT procedure enjoys model selection consistency. Extensive simulation studies and a real data analysis for selecting skilled funds in the U.S. financial market are presented to illustrate the practical utility of the proposed method. Supplementary materials for this article are available online. 相似文献
114.
In this paper, we consider the laws of large numbers for NSD random variables satisfying Pareto-type distributions with infinite means. Based on the Pareto-Zipf distributions, some weak laws of large numbers for weighted sums of NSD random variables are obtained. Meanwhile, we show that a weak law for Pareto-Zipf distributions cannot be extended to a strong law. Furthermore, based on the two tailed Pareto distribution, a strong law of large numbers for weighed NSD random variables is presented. Our results extend the corresponding earlier ones. 相似文献
115.
Wei Li Kanika Bakshi Yining Tan Xuanyu Huang 《International migration (Geneva, Switzerland)》2019,57(3):373-391
Despite the continuous asymmetrical power relations between the Global North and South, the “global race for talent” is no longer a privilege enjoyed only by developed countries. Comparative analysis of policy content and effectiveness has attracted increasing interest. The examination of policy initiatives resulting in return migration of highly‐skilled migrants from the Global North to the Global South, however, remains inadequate. In this article, we provide a comparative analysis of policies targeting high‐level Chinese and Indian professionals including full‐time returnees. Two key differences in policy instruments and outcomes in the two countries are identified and they have implications for migration policies in other countries in the Global South and North. 相似文献
116.
This paper examines the effects of exchange rate depreciation to the U.S. economy in a factor‐augmented vector autoregression model using monthly data of 148 variables for the post–Bretton Woods period of 1973–2017. Exchange rate shock is identified to reflect exogenous disturbances to the foreign exchange market, and movements in exchange rate that are not accounted for by changes in the U.S. monetary policy. We find that depreciation is expansionary and inflationary to the broad U.S. economy, the current account improves over time conforming to the J‐curve theory, and monetary policy is leaning against the wind. (JEL E3, E5, F31, F32, F41) 相似文献
117.
Lighting plays an important role in daily life: It helps people perform daily activities independently and safely, and also benefits their health. This study assesses the research evidence of lighting’s impacts on older adults in four domains: (a) performance of activities of daily living and instrumental activities of daily living; (b) circadian rhythm; (c) fall prevention and postural stability; and (d) sleep quality. A comprehensive review of lighting studies on older adults’ visual and nonvisual performance was conducted using a modified PRISMA systematic review process. For the first domain, some older adults had difficulty in using the toilet, preparing meals, and doing laundry under lower illuminance. For the second domain, brighter and bluish lighting improved older adults’ circadian rhythm. For the third domain, low-intensity LED lighting affixed on door frames can help older adults maintain postural stability and prevent falling during nighttime movement. Finally, some studies concluded that receiving outdoor daylight during exercise was beneficial to older adults’ sleep quality. This study provides several methodological, theoretical, and collaborative suggestions for developing a more conclusive evidence base for lighting standards and strategies for older adults. 相似文献
118.
Lu Jiahuan Lin Weiwei Wang Qiushi 《Voluntas: International Journal of Voluntary and Nonprofit Organizations》2019,30(3):593-609
VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - This article explores how and to what extent revenue diversification and concentration strategies affect financial... 相似文献
119.
The shared resource hypothesis suggests that married couples share the same environmental resources, which shape their health concordance. This study tests its cross‐national applicability. Cross‐sectional 2012–2013 Health and Retirement Study data from China, England, Mexico, and the United States were analyzed. Heterosexual couples (age ≥60) who were married or partnered were studied (N = 20,565 pairs). Dyadic data were analyzed by multilevel models to examine the effect of self and spousal social and physical health statuses on depressive symptoms. Regression models were used to test the relationship between couples' shared resources and depressive symptom concordance. Results indicated both husbands and wives' depressive symptoms were associated with their own and spouses' social and health statuses. Most couple‐level resources were insignificant predictors for Chinese and Mexican couples' concordance, but having more social and financial resources was associated with higher concordance among British and American couples. Self‐reported health was the most consistent predictor in all countries. The shared resource hypothesis was more applicable to depressive symptom concordance within couples in the United States and England, but not in China and Mexico. Couple‐centered intervention is suggested for clinical practice, and the spousal effect should be considered in policymaking. 相似文献
120.
Shiyu Lu 《Journal of social service research》2019,45(2):241-253
Community-based elder care has become a dominant model in the world. However, the role of community-level factors in helping or hindering the individuals concerned in obtaining the needed care has not received much attention. This research aims to investigate how community-level factors, including neighborhood disadvantage, residential instability, and social service environment affect the need for instrumental, medical, and emotional services of Chinese senior residents. Employing the hierarchical multiple regression analysis, the results show that instrumental activities of daily living impairment contributed significantly to the need for instrumental, medical and emotional services. Living alone was found to be associated with the need for medical and emotional services. Objective socioeconomic status was only significantly related to the need for medical care. The type of urban community was positively associated with the need for instrumental services and was negatively related to the need for medical care. Residential instability was positively associated with of the need for instrumental services and medical care. Social service environments had heterogeneous effects on the need for social services. However, neighborhood disadvantage had no significant impact on the need for social services. Implications for future research and policy reform were also discussed. 相似文献