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1.
Adolescents’ time spent messaging, exploring websites, and studying on the computer increased between 2003 and 2008. Using data from the Panel Study of Income Dynamics Child Development Supplement, this study examines how such changes have influenced individual achievement and behavior from childhood to adolescence. Greater communications and Internet web time proved detrimental to vocabulary and reading whereas the increased use of computer games was associated with increased reading and problem‐solving scores, particularly for girls and minority children. Increased use of the computer for studying was associated with increased test scores for girls, but not boys. The consequences are more benign than many feared. Groups that have traditionally used the computer less (girls, minority children) appear to benefit from greater use.  相似文献   
2.
This paper derives Akaike information criterion (AIC), corrected AIC, the Bayesian information criterion (BIC) and Hannan and Quinn’s information criterion for approximate factor models assuming a large number of cross-sectional observations and studies the consistency properties of these information criteria. It also reports extensive simulation results comparing the performance of the extant and new procedures for the selection of the number of factors. The simulation results show the di?culty of determining which criterion performs best. In practice, it is advisable to consider several criteria at the same time, especially Hannan and Quinn’s information criterion, Bai and Ng’s ICp2 and BIC3, and Onatski’s and Ahn and Horenstein’s eigenvalue-based criteria. The model-selection criteria considered in this paper are also applied to Stock and Watson’s two macroeconomic data sets. The results differ considerably depending on the model-selection criterion in use, but evidence suggesting five factors for the first data and five to seven factors for the second data is obtainable.  相似文献   
3.
In electronics Fabs such as semiconductor Fabs and liquid crystal display (LCD) Fabs, which are capital-intensive, finite-capacity planning is critical to achieving full-capacity production and on-time production. However, existing finite-capacity planning methods do not adequately reflect the actual capacity profiles of an electronics Fab. In this paper, we propose a new Fab-level capacity-filtering procedure to generate finite-capacity plan: a backward capacity-filtering procedure for generating finite-capacity release plan. When developing the Fab-level filtering procedures, we use stage-level capacity-filtering algorithms as a key building block. In this study, we enhance the previous capacity-filtering algorithms proposed by one of the authors in order to facilitate the practical requirements of electronics Fabs. We apply the proposed capacity-filtering method to a modern LCD–TFT Fab in Korea. Performance analyses demonstrate that the proposed method is superior to existing methods.  相似文献   
4.
We investigate resolute voting rules that always rank two alternatives strictly and avoid social indecision. Resolute majority rules differ from the standard majority rule in that whenever both alternatives win the same number of votes, a tie-breaking function is used to determine the outcome. We provide axiomatic characterizations of resolute majority rules or resolute majority rules with a quorum. Resoluteness axiom is used in all these results. The other axioms are weaker than those considered in the characterization of the majority rule by May (1952 Econometrica, 20:680–684). In particular, instead of May’s positive responsiveness, we consider a much weaker monotonicity axiom.  相似文献   
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6.
In response to a low fertility rate, a number of municipalities in South Korea have been providing family benefits in the form of childbirth grants and child allowances. Using panel data for 230 municipalities that spans the years 2001–2014, this paper examines the impacts of family benefits on the fertility rate in Korea. I use the fact that different municipalities began providing the family benefits at different times to estimate the impact of family benefits on fertility rates using a difference-in-differences approach. This study finds a positive effect of family benefits on total fertility rate. Moreover, it finds little evidence of an anticipatory response within municipalities that adopted the policy. Given that a 10 million Korean won increase in family benefits is associated with a 3.5% increase in the total fertility rate, an increase in family benefits of about 44 million Korean won per child would be required to raise the total fertility rate to a safe zone above 1.5 children per woman, where population declines are gradual and easily reversed.  相似文献   
7.
Career counselors must continually enhance their knowledge and skills to assist clients contemplating careers in science, technology, engineering, and mathematics (STEM). Therefore, the authors review STEM disciplines and theory‐driven strategies for assisting diverse individuals to explore, enter, and persist in STEM careers. Appropriate use of career assessments can contribute greatly to this effort. To identify available measures for STEM‐focused domains and constructs, the authors conducted a journal content analysis of stand‐alone STEM‐related career assessments from 1983 to 2016, identifying 39 articles with 153 measures. Notable results included the emergence of social cognitive theory and social cognitive career theory as prevailing frameworks for instrument development, a wide variety of disciplines and journals represented, an underrepresentation of minority samples, and untapped potential for cross‐discipline and researcher–practitioner collaboration. Useful strategies and resources for counselors and recommendations for enhancing career assessments and interventions are addressed.  相似文献   
8.
This study proposes necessary modifications to the existing internationalization–performance relationship to meet the idiosyncrasies of China-specific contexts. We first hypothesize an S-shaped internationalization–performance relationship as the baseline and then investigate the moderating effects of a firm's governance structure and the degree of centralized government control on the relationship between its internationalization and performance. The results, based on a longitudinal sample of manufacturing firms in China for the 2001–2007 period, indicate that (1) the S-shaped internationalization–performance relationship holds for firms in China; (2) the governance structure moderates the internationalization–performance relationship such that increased profitability through internationalization is more likely for modernized firms than for their conventional local counterparts; and (3) the degree of centralized control moderates the internationalization–performance relationship such that increased profitability through internationalization is more likely for firms affiliated with higher level governments than for those affiliated with lower-level governments.  相似文献   
9.
Ha  Il Do  Xiang  Liming  Peng  Mengjiao  Jeong  Jong-Hyeon  Lee  Youngjo 《Lifetime data analysis》2020,26(1):109-133
Lifetime Data Analysis - In the semi-competing risks situation where only a terminal event censors a non-terminal event, observed event times can be correlated. Recently, frailty models with an...  相似文献   
10.
Has the rise in globalization reduced U.S. inflation in the 1990s?   总被引:3,自引:0,他引:3  
This article investigates whether increased globalization of the U.S. economy has helped hold down inflation in the 1990s. Based on several measures, we find that globalization has increased. Further, we find that import prices exert a greater impact on prices of products in industries faced with greater import penetration. High foreign excess capacity accounts for much of the recent decline in U.S. inflation. Our results suggest that the decline in inflation is explained by the interaction of increased globalization and high excess foreign capacity. Globalization by itself does not lead to less inflation, just greater sensitivity to foreign economic conditions.  相似文献   
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