• 제목/요약/키워드: Associated random variables

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Simple Statistical Tools to Detect Signals of Recent Polygenic Selection

  • Piffer, Davide
    • Interdisciplinary Bio Central
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    • 제6권1호
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    • pp.1.1-1.6
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    • 2014
  • A growing body of evidence shows that most psychological traits are polygenic, that is they involve the action of many genes with small effects. However, the study of selection has disproportionately been on one or a few genes and their associated sweep signals (rapid and large changes in frequency). If our goal is to study the evolution of psychological variables, such as intelligence, we need a model that explains the evolution of phenotypes governed by many common genetic variants. This study illustrates simple statistical tools to detect signals of recent polygenic selection: a) ANOVA can be used to reveal significant deviation from random distribution of allele frequencies across racial groups. b) Principal component analysis can be used as a tool for finding a factor that represents the strength of recent selection on a phenotype and the underlying genetic variation. c) Method of correlated vectors: the correlation between genetic frequencies and the average phenotypes of different populations is computed; then, the resulting correlation coefficients are correlated with the corresponding alleles' genome-wide significance. This provides a measure of how selection acted on genes with higher signal to noise ratio. Another related test is that alleles with large frequency differences between populations should have a higher genome-wide significance value than alleles with small frequency differences. This paper fruitfully employs these tools and shows that common genetic variants exhibit subtle frequency shifts and that these shifts predict phenotypic differences across populations.

Changes in Co-Occurrence of Smoking and Harmful Drinking among Youth: a Study from the Chi Linh Demographic - Epidemiological Surveillance System in Vietnam, 2006-2013

  • Duong, Minh Duc;Le, Thi Vui;Nguyen, Thuy Quynh;Hoang, Van Minh
    • Asian Pacific Journal of Cancer Prevention
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    • 제17권sup1호
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    • pp.55-63
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    • 2016
  • Smoking and harmful drinking dramatically increase health risks but little is known about their cooccurrence and factors that influence this co-habit, limiting development and implementation of appropriately targeted prevention interventions. This study was conducted among youth aged 10-24 years old in the Chi Linh Demographic - Epidemiological Surveillance System (CHILILAB DESS). The total numbers in the first, second and third rounds in 2006, 2009 and 2013 were 12,406, 10,211, and 7,654, respectively. A random-effects logit model controlling for both time-variant and time-invariant variables was applied to explore factors associated with current smoking, harmful drinking, and occurrence of smoking and harmful drinking together. We found dramatically increasing trends in current smoking, harmful drinking and co-occurrence among youth. Our results indicate similar health problems among youth in peri-urban areas in Vietnam. Demographic characteristics (older age, being male, being unmarried, and having informal work) appeared to be predictors for smoking and drinking behaviour. Besides, peer and family members had significant influence on smoking, whereas having a close-friend who was smoking was the most important variable. The results suggested that smoking and harmful drinking should not be solved with separate, stand-alone interventions but rather with integrated efforts.

Discriminative Factor Analysis of Juvenile Delinquency in South Korea

  • Kim, Hyun-Sil;Kim, Hun-Soo
    • 대한간호학회지
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    • 제36권8호
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    • pp.1315-1323
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    • 2006
  • Purpose. The present study was intended to compare difference in research variables between delinquent adolescents and student adolescents, and to analyze discriminative factors of delinquent behaviors among Korean adolescents. Methods. The research design of this study was a questionnaire survey. Questionnaires were administered to 2,167 adolescents (1,196 students and 971 delinquents), sampled from 8 middle and high school and 6 juvenile corrective institutions, using the proportional stratified random sampling method. Statistical methods employed were Chi-square, t-test, and logistic regression analysis. Results. The discriminative factors of delinquent behaviors were smoking, alcohol use, other drug use, being sexually abused, viewing time of media violence and pornography. Among these discriminative factors, the factor most strongly associated with delinquency was smoking (odds ratio: 32.32). That is, smoking adolescent has a 32-fold higher possibility of becoming a delinquent adolescent than a non-smoking adolescent. Conclusions. Our findings, that smoking was the strongest discriminative factor of delinquent behavior, suggest that educational strategies to prevent adolescent smoking may reduce the rate of juvenile delinquency. Antismoking educational efforts are therefore urgently needed in South Korea.

Predictors of Cancer Awareness among Older Adult Individuals in Jordan

  • Ahmad, Muayyad M.;Al-Gamal, Ekhlas
    • Asian Pacific Journal of Cancer Prevention
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    • 제15권24호
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    • pp.10927-10932
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    • 2015
  • Background: Older age is associated with an increase in the incidence of cancer cases. Diagnosis and treatment of cancer in older adults can be stressful because of health decline related to age, comorbidities and inadequate treatment for pain and other symptoms of the disease. This survey is one of the unique studies in Jordan and in the Arab world that aimed at exploring the predictors of older adult individuals awareness towards cancer. Materials and Methods: A stratified random sampling technique was followed to reach a representative sample of 753 participants. The questionnaire of the study consisted of parts regarding demographic variables, awareness about screening tests, and signs and symptoms of cancer. In addition, specific questions related to factors linked to cancer were included. Cross-sectional design was adopted with face-to-face interviews at the interviewees' households. Results: The mean age of the participants was about 63 years; around 44% of them are above the age of 65 years. 'Being convinced that having no health problem makes the individual feel safe and not at risk of getting cancer' was the major reason for not doing a routine health check-up. Conclusions: The low levels of awareness about cancer, as well as the low use of the screening methods were crucial outcomes of this study. Thus, raising the awareness among health care providers and policy makers in the country about older adults' perception of cancer is a high priority.

Intergenerational Transfers Between Parents and Their Multiple Adult Children in South Korea

  • Choi, Saeeun;Kim, Jinhee
    • International Journal of Human Ecology
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    • 제15권2호
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    • pp.69-80
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    • 2014
  • Guided by the exchange model, altruistic model, intergenerational solidarity theory, and cultural contexts, this study explored the determinants of financial intergenerational transfers between older parents and adult children in South Korea. We examined 18,820 parent-child dyads by using random-effects models on the first wave of the Korean Longitudinal Study of Ageing (KLoSA) data. Findings showed that downward financial intergenerational transfers were consistent with the self-interest exchange model but upward transfers did not support microeconomic theories. Family solidarity theory was generally supported by downward transfers but geographical proximity was not positively associated with upward transfers. Lastly, cultural contextual variables such as marital status, birth order, and sex of a child were found to be significant. Parents tended to both provide and receive more financial support from unmarried children than from married children. Within the same marital status, the hierarchy existed in order of the first-born son, the second or later sons, and daughters when it came to downward financial transfers. Regarding upward financial transfers, the preference in order was more complicated. The findings of this study help in understanding the intergenerational financial transfers in the Korean context.

Sum Rate Approximation of Zero-Forcing Beamforming with Semi-Orthogonal User Selection

  • Yang, Jang-Hoon;Jang, Seung-Hun;Kim, Dong-Ku
    • Journal of Communications and Networks
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    • 제12권3호
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    • pp.222-230
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    • 2010
  • In this paper, we present a closed-form approximation of the average sum rate of zero-forcing (ZF) beamforming (BF) with semi-orthogonal user selection (SUS). We first derive the survival probability associated with the SUS that absolute square of the channel correlation between two users is less than the orthogonalization level threshold (OLT).With this result, each distribution for the number of surviving users at each iteration of the SUS and the number of streams for transmission is calculated. Secondly, the received signal power of ZF-BF is represented as a function of the elements of the upper triangular matrix from QR decomposition of the channel matrix. Thirdly, we approximate the received signal power of ZF-BF with the SUS as the maximum of scaled chisquare random variables where the scaling factor is approximated as a function of both OLT and the number of users in the system. Putting all the above derivations and order statistics together, the approximated ergodic sum rate of ZF-BF with the SUS is shown in a closed form. The simulation results verify that the approximation tightly matches with the sample average for any OLT and even for a small number of users.

The Impact of Operating Cash Flows on Financial Stability of Commercial Banks: Evidence from Pakistan

  • ELAHI, Mustahsan;AHMAD, Habib;SHAMAS UL HAQ, Muhammad;SALEEM, Ali
    • The Journal of Asian Finance, Economics and Business
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    • 제8권11호
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    • pp.223-234
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    • 2021
  • This study aims to examine whether operating cash flows influence banks' financial stability in Pakistan. The study employed annual panel data collected from annual reports of 20 commercial banks listed on the Pakistan Stock Exchange for the year 2011 to 2019. Free cash flow yield was taken as the dependent variable while cash flow ratio was selected as the independent variable, and net interest margin, income diversification, asset quality, financial leverage, the cost to income ratio, advance net of provisions to total assets ratio, capital ratio, financial performance, breakup value per share and bank size were taken as control variables. The study performed ordinary least square technique, random and fixed effects models, Hausman test, Lagrange multiplier test, descriptive and correlation analysis. Results showed that operating cash flows and net interest margin significantly and positively influenced banks' financial stability while the cost to income ratio and advances net of provisions to total assets ratio significantly and negatively associated with banks' financial stability. To improve financial stability, banks should become more cost-effective and enhance their liquidity levels by lowering lending activities. In the future, it would be useful to compare commercial and investment banks, also Islamic and conventional banks in the same research setting.

Economic Growth, Financial Development, and Trade Openness of Leading Countries in ASEAN

  • HO, Chi H.P.;PHAM, Nhan N.T.;NGUYEN, Kiet T.
    • The Journal of Asian Finance, Economics and Business
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    • 제8권3호
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    • pp.191-199
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    • 2021
  • The study examines the causal relationship between financial development and economic growth through trade openness for the leading ASEAN countries (Indonesia, the Philippines, Malaysia, Singapore, Thailand, and Vietnam). The study employs a panel data for the period of 25 years spanning from 1995 to 2015 for the six countries, yielding a balanced panel of 150 observations. Fixed effect model (FEM) and random effect model (REM) are used for the panel data, following the Hausman test performed for model selection. The trivariate Granger causality test is also used to check for possible relationship between the variables. The results show that REM is chosen based on the Hausman test result, suggesting that the trade openness has a positive association with growth whereas the financial development is positively, but insignificantly associated with growth. The reason for this is that the financial development and economic growth may be related to each other. The results are, then, further explored and confirmed by the causality test. That is, the financial development and the economic growth, through the trade openness, are found to have bidirectional positive relationships. This implies that there would be shortcomings when ignoring the presence of trade openness, which positively impacts the relationship between finance and growth.

The Impact of Innovation Activities on Firm Efficiency: Data Envelopment Analysis

  • PHAM, Tien Phat;QUDDUS, Abdul
    • The Journal of Asian Finance, Economics and Business
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    • 제8권3호
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    • pp.895-904
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    • 2021
  • This study aims to investigate the impact of innovation on firm efficiency. Panel data of fourteen finance companies and nine technology companies from 2011 to 2019 on the Vietnam Stock Exchange Market is derived from audited financial statements, annual reports, and other crucial reports that are provided by Vietstock; macroeconomic variables are collected from the World Bank Database. A two-stage approach is used. First, use of the Data Envelopment Analysis methodology to measure firm efficiency. Second, use of the Pooled ordinary least squares, the Fixed effects model, and the Random effects model to investigate the impact of innovation on firm efficiency. Furthermore, the Generalized Method of Moments and the Tobit model are used to validate the impact of innovation on firm efficiency, and the t-test is used to confirm the difference in efficiency with and without the impact of innovation between two industries. The results show that there is a significant impact of innovation on efficiency, and innovation plays a more important in increasing the efficiency of the finance industry than the technology industry. Moreover, the relation between age and efficiency is like the U-shaped, and between size and efficiency is like the inverted U-shaped, whereas efficiency is not associated with inflation.

Socio-Demographic Correlates of Participation in Mammography: A Survey among Women Aged between 35-69 in Tehran, Iran

  • Samah, Asnarulkhadi Abu;Ahmadian, Maryam
    • Asian Pacific Journal of Cancer Prevention
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    • 제13권6호
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    • pp.2717-2720
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    • 2012
  • Background: The rates of breast cancer have increased over the past two decades, and this raises concern about physical, psychological and social well-being of women with breast cancer. Further, few women really want to do breast cancer screening. We here investigated the socio-demographic correlates of mammography participation among 400 asymptomatic Iranian women aged between 35 and 69. Methods: A cross-sectional survey was conducted at the four outpatient clinics of general hospitals in Tehran during the period from July through October, 2009. Bi-variate analyses and multi-variate binary logistic regression were employed to find the socio-demographic predictors of mammography utilization among participants. Results: The rate of mammography participation was 21.5% and relatively high because of access to general hospital services. More women who had undergone mammography were graduates from university or college, had full-time or part-time employment, were insured whether public or private, reported a positive family history of breast cancer, and were in the middle income level (all P<0.01).The largest number of participating women was in the age range of 41 to 50 years. The results of multivariate logistic regression further showed that education (95%CI: 0.131-0.622), monthly income (95%CI: 0.038-0.945), and family history of breast cancer (95%CI: 1.97-9.28) were significantly associated (all P<0.05) with mammography participation. Conclusions: The most important issue for a successful screening program is participation. Using a random sample, this study found that the potential predictor variables of mammography participation included a higher education level, a middle income level, and a positive family history of breast cancer for Iranian women, after adjusting for all other demographic variables in the model.