• Title/Summary/Keyword: Pooled Mean Group

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The Macroeconomic and Institutional Drivers of Stock Market Development: Empirical Evidence from BRICS Economies

  • REHMAN, Mohd Ziaur
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.2
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    • pp.77-88
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    • 2021
  • The stock markets in the BRICS (Brazil, Russia, India, China and South Africa) countries are the leading emerging markets globally. Therefore, it is pertinent to ascertain the critical drivers of stock market development in these economies. The currrent study empirically investigates to identify the linkages between stock market development, key macro-economic factors and institutional factors in the BRICS economies. The study covers the time period from 2000 to 2017. The dependent variable is the country's stock market development and the independent variables consist of six macroeconomic variables and five institutional variables. The study employs a panel cointegration test, Fully Modified OLS (FMOLS), a Pooled Mean Group (PMG) approach and a heterogeneous panel non-causality test.The findings of the study indicate co-integration among the selected variables across the BRICS stock markets. Long-run estimations reveal that five macroeconomic variables and four variables related to institutional quality are positive and statistically significant. Further, short-run causalities between stock market capitalization and selected variables are detected through the test of non-causality in a heterogeneous panel setting. The findings suggest that policymakers in the BRICS countries should enhance robust macroeconomic conditions to support their financial markets and should strengthen the institutional quality drivers to stimulate the pace of stock market development in their countries.

Dynamic Elasticities Between Financial Performance and Determinants of Mining and Extractive Companies in Jordan

  • Yusop, Nora Yusma;Alhyari, Jad Alkareem;Bekhet, Hussain Ali
    • The Journal of Asian Finance, Economics and Business
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    • v.8 no.7
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    • pp.433-446
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    • 2021
  • This study aims to identify the elasticities and casualties of financial performance and determinants of the mining and extractive companies listed in Jordan's stock market over the 2005-2018 period. The conceptual framework is based on the Resource-Based View theory and Arbitrage Pricing theory is used to describe the relationship between the external environment and the financial performance of the companies. Profitability ratio (return on assets) is utilized as a proxy of financial performance measurement. Meantime, the company's characteristics, macroeconomic variables, and non-economic factors are utilized as independent factors. Data sources are panel data set for mining and extractive companies over the above period. Fully Modified Ordinary Least Square (FMOLS), Dynamic Ordinary Least Squares (DOLS), and Pooled Mean Group (PMG) methods are applied. The empirical findings indicated that company size, sales growth, financial leverage, liquidity, and GDP growth were the critical determinants of mining and extractive companies' financial performance in the Amman Stock Exchange. Thus, the findings conclude that company characteristics and GDP growth mainly drive financial performance. Moreover, the findings reveal that a bidirectional causal elasticity exists between GDP and financial leverage and return on assets (ROA). Sound financial performance can be obtained by paying more attention to GDP growth and firms' characteristics.

Relationship between psychological stress and hippocampus volume through meta-analysis (메타분석을 통한 심리적 스트레스와 해마용적 간의 관계)

  • Jo, Min-kyung;Hong, Changhee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.12
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    • pp.227-236
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    • 2018
  • This study was conducted to define hippocampal volume differences between a stress-laid group and normal individual group via meta-analysis. This investigation included studies that contained hippocampal volume measurements in association with stress from 1990 to 2016. Magnetic resonance imaging (MRI) measurements of hippocampal volumes were used to determine the mean size, standard deviation and sample size. The pooled effect size was measured by the standardized mean difference (SMD) with a 95% confidence interval. This meta-analysis included 13 studies comprising 374 stress subjects and 439 normal subjects. Eight studies targeted war-related veterans and holocaust survivors, while five targeted personal trauma associated with childhood abuse, rape, accident or financial hardship. The overall mean effect size (Hedges' g) was -0.70 (-1.04; -0.37). Overall, the SMD value was -0.70, with a moderate effect size, but high heterogeneity. Depending on the characteristics of the stressor, studies were divided by subgroups of war-related veterans and subjects with personal trauma and then analyzed again. In the war-related subgroup, the Hedges' g was -0.47 (-0.78; -0.16), while in the personal stressor-related subgroup it was -0.91 (-1.57; -0.26). These results indicate that there was a significant negative correlation between psychological stress and hippocampal volume.

Line-by-Level of Chitosan Interaction on Egg Traits and Yolk Cholesterol Level in Laying Hens (계란형질들과 난황 콜레스테롤 수준에 대한 닭의 계통과 키토산의 첨가 수준간의 상호작용 효과)

  • 석윤오;서형철
    • Korean Journal of Poultry Science
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    • v.29 no.2
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    • pp.81-88
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    • 2002
  • The objective of this study was to investigate the line-by-feed additive interaction on egg traits and yolk cholesterol level in laying hens. Hy-line W-98 (white shell line) and Hy-line Brown (brown shell line) were used as experimental stocks and three groups were assigned in each line. The age of hens used in this study were from 40- to 46-wk-old. Two different levels of chitosan were also used as additive in chicken diet. The first (CH$_{30}$) and second (CH$_{60}$) experimental groups were fed basal diet added 30mg and 60mg chitosan/kg feed, respectively. And the control group (CON) hens were fed with basal diet only. The eggs were collected and analyzed at the end of 40, 42, 44, and 46-wk-old. In the mean egg weight, the CH$_{30}$ in Hy-line Brown was significantly heavier (P<0.05) than CON, but the CH$_{30}$ in Hy-line W-98 was significantly lighter (P<0.05) than CON. Whereas, the mean egg weight did not significantly differ between CH$_{60}$ and CON in both line. The mean albumen percentage in Hy-line Brown did not show significant between experimental groups and control group. On the other hand, the mean albumen percentage of CH$_{60}$ in Hy-line W-98 was significantly lower (P < 0.05) than that of CON, but there was no significantly different between CH$_{30}$ and CON. In the mean yolk percentage, it showed a reverse trend as shown in the mean albumen percentage; there were significantly higher (P<0.05) in CH$_{60}$ than in CON fur the Hy-line W-98, and higher in CH$_{30}$ than in CON for the Hy-line Brown. However, the mean shell percentages did not significantly differ between experimental groups and control group in both lines. In the mean yolk cholesterol levels, the CH$_{30}$ and CH$_{60}$ in both lines were lower by 0.46 mg ∼2.80 mg per gram yolk than CON. Although the interaction effect of line-by-supplementing level of chitosan in hens diet on the pooled mean of yolk cholesterol level was no significant, it showed a highly significant interaction (P<0.01) at three of four experimental ages.

Standardized Breast Cancer Mortality Rate Compared to the General Female Population of Iran

  • Haghighat, S.;Akbari, M.E.;Ghaffari, S.;Yavari, P.
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.11
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    • pp.5525-5528
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    • 2012
  • Introduction: Breast cancer is the most common cancer in women. Improvements of early diagnosis modalities have led to longer survival rates. This study aimed to determine the 5, 10 and 15 year mortality rates of breast cancer patients compared to the normal female population. Materials and Methods: The follow up data of a cohort of 615 breast cancer patients referred to Iranian Breast Cancer Research Center (BCRC) from 1986 to 1996 was considered as reference breast cancer dataset. The dataset was divided into 5 year age groups and the 5, 10 and 15 year probability of death for each group was estimated. The annual mortality rate of Iranian women was obtained from the Death Registry system. Standardized mortality ratios (SMRs) of breast cancer patients were calculated using the ratio of the mortality rate in breast cancer patients over the general female population. Results: The mean age of breast cancer patients at diagnosis time was 45.9 (${\pm}10.5$) years ranging from 24-74. A total of 73, 32 and 2 deaths were recorded at 5, 10 and 15 years, respectively, after diagnosis. The SMRs for breast cancer patients at 5, 10 and 15 year intervals after diagnosis were 6.74 (95% CI, 5.5-8.2), 6.55 (95%CI, 5-8.1) and 1.26 (95%CI, 0.65-2.9), respectively. Conclusion: Results showed that the observed mortality rate of breast cancer patients after 15 years from diagnosis was very similar to expected rates in general female population. This finding would be useful for clinicians and health policy makers to adopt a beneficial strategy to improve breast cancer survival. Further follow-up time with larger sample size and a pooled analysis of survival rates of different centres may shed more light on mortality patterns of breast cancer.

Increased Sister Chromatid Exchange in Peripheral Blood Lymphocytes from Humans Exposed to Pesticide: Evidence Based on a Meta-analysis

  • Yang, Hai-Yan;Liu, Jing;Yang, Si-Yu;Wang, Hai-Yu;Wang, Ya-Dong
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.22
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    • pp.9725-9730
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    • 2014
  • Background: Sister chromatid exchange (SCE) in human peripheral blood lymphocytes is one of the most extensively studied biomarkers employed to evaluate genetic damage subsequent to pesticide exposure. Objective: To estimate the pooled levels of SCE in human peripheral blood lymphocytes among population exposed to pesticide. Materials and Methods: Meta-analysis on the association between SCE frequency and pesticide exposure was performed with STATA 10.0 software package and Review Manager 5.0.24 in this study. Results: The overall means of SCE were 7.88 [95% confidence intervals (95%CI): 6.71-9.04] for exposure group and 6.05 (95%CI: 5.13-6.95) for controls, respectively. There was statistically significant difference in the SCE frequency in human peripheral blood lymphocytes between pesticide-exposed groups and control groups, and the summary estimate of weighted mean difference was 1.69 (95%CI: 1.01-2.38). We also observed that pesticide-exposed population had significantly higher SCE frequency than control groups among smokers, nonsmokers, pesticide applicator, pesticide producer, other exposure population and Asian population in stratified analyses. Conclusions: Data indicate that the SCE frequency in human peripheral blood lymphocytes might be an indicator of early genetic esffects for pesticide-exposed populations.

Effect of feeding fermented soybean meal on broiler chickens' performance: a meta-analysis

  • Irawan, Agung;Ratriyanto, Adi;Respati, Adib Norma;Ningsih, Niati;Fitriastuti, Rahma;Suprayogi, Wara Pratitis Sabar;Hadi, Rendi Fathoni;Setyono, Wahyu;Akhirini, Novi;Jayanegara, Anuraga
    • Animal Bioscience
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    • v.35 no.12
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    • pp.1881-1891
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    • 2022
  • Objective: The present study aimed to quantify the effects of fermented soybean meal (FSBM) on broiler chickens' performance by employing a meta-analysis approach. Methods: A total of 16 studies were included in the database after being systematically selected using a PRISMA protocol. Hedges' g effect size was used to quantify pooled standardized mean difference (SMD) using random-effects models at 95% confidence intervals (95% CI). Publication bias among studies was computed with Egger's test and visualized using funnel plots. Results: Results indicated that dietary FSBM inclusion increased final body weight (BW) (SMD = 0.586, 95% CI: 0.221 to 0.951, p = 0.002) of broiler chickens, particularly in starter period (SMD = 0.691, 95% CL: 0.149 to 1.233, p = 0.013) while in the finisher period, the effect was weaker (SMD = 0.509, 95% CI: 0.015 to 1.004, p = 0.043). Average daily gain (ADG), feed intake (FI), and feed conversion ratio (FCR) were not affected with FSBM inclusion when compared to control. Subgroup analysis revealed that FI increased in starter period (SMD = 0.582, 95% CI: 0.037 to 1.128, p = 0.036). When considering types of microorganism as moderating variables in the subgroup analysis, we found that Aspergillus oryzae, mixed probiotics+bromelain protease, Bacillus subtilis, and Lactobacillus bacteria significantly increased ADG and FI (p<0.01). Additionally, either Bacillus subtilis+protease or Bacillus subtilis alone decreased FCR (p<0.001). However, meta-regression analysis showed that levels of FSBM inclusion had no effects on final BW (p = 0.502), ADG (p = 0.588), FI (p = 0.861), and FCR (p = 0.462). Conclusion: Substituting SBM in broiler chickens' diet with FSBM improved BW of broiler chickens, especially in the starter period whereas the effects on ADG, FI, and FCR were mostly dependent on microbial strains used for fermentation.

Incorporating a continuous suction system as a preventive measure against fistula-related complications in head and neck reconstructive surgery

  • Chang, Hsien Pin;Hong, Jong Won;Lee, Won Jai;Kim, Young Seok;Koh, Yoon Woo;Kim, Se-Heon;Lew, Dae Hyun;Roh, Tae Suk
    • Archives of Plastic Surgery
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    • v.45 no.5
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    • pp.449-457
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    • 2018
  • Background Although previous studies have focused on determining prognostic and causative variables associated with fistula-related complications after head and neck reconstructive surgery, only a few studies have addressed preventive measures. Noting that pooled saliva complicates wound healing and precipitates fistula-related complications, we devised a continuous suction system to remove saliva during early postoperative recovery. Methods A continuous suction system was implemented in 20 patients after head and neck reconstructive surgery between January 2012 and October 2017. This group was compared to a control group of 16 patients at the same institution. The system was placed orally when the lesion was on the anterior side of the retromolar trigone area, and when glossectomy or resection of the mouth floor was performed. When the orohypopharynx and/or larynx were eradicated, the irrigation system was placed in the pharyngeal area. Results The mean follow-up period was $9.2{\pm}2.4$ months. The Hemovac system was applied for an average of 7.5 days. On average, 6.5 days were needed for the net drain output to fall below 10 mL. Complications were analyzed according to their causes and rates. A fistula occurred in two cases in the suction group. Compared to the control group, a significant difference was noted in the surgical site infection rate (P<0.031). Conclusions Clinical observations showed reduced saliva pooling and a reduction in the infection rate. This resulted in improved wound healing through the application of a continuous suction system.

Analysis on Socio-cultural Aspect of Willingness to Pay for Air Quality (PM10, PM2.5) Improvement in Seoul (서울지역 미세먼지 문제 개선을 위한 사회문화적 지불의사액 추정)

  • Kim, Jaewan;Jung, Taeyong;Lee, Taedong;Lee, Dong Kun
    • Journal of Environmental Impact Assessment
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    • v.28 no.2
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    • pp.101-112
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    • 2019
  • Over the last few years, air pollution ($PM_{10}$, $PM_{2.5}$) in the Seoul metropolitan area (SMA) has emerged as one of the most concerned and threatening environmental issues among the residents. It brings about various harmful effects on human health, as well as ecosystem and industrial activities. Governments and individuals pay various costs to mitigate the level of air pollutants. This study aims to empirically find the willingness to pays (WTP) among the parents from different socio-cultural groups - international and domestic groups to mitigate air pollution ($PM_{10}$, $PM_{2.5}$) in their residential area. Contingent Valuation Methods (CVM) is used with employing single-bounded dichotomous choice technique to elicit the respondent's WTP. Using tobit (censored regression) and probit models, the monthly mean WTP of the pooled sample for green electricity which contributes to improve air quality in the region was estimated as 3,993 KRW (3.58 USD). However, the mean WTP between the international group and domestic group through a sub-sample analysis shows broad distinction as 3,325KRW (2.98 USD) and 4,449 KRW (3.98 USD) respectively. This is because that socio-cultural characteristics of each group such as socio-economic status, personal experience, trust in institutions and worldview are differently associated with the WTP. Based on the results, the society needs to raise awareness of lay people to find a strong linkage between the current PM issue and green electricity. Also, it needs to improve trust in the government's pollution abatement policy to mobilize more assertive participation of the people from different socio-cultural background.

Full-Endoscopic versus Minimally Invasive Lumbar Interbody Fusion for Lumbar Degenerative Diseases : A Systematic Review and Meta-Analysis

  • Son, Seong;Yoo, Byung Rhae;Lee, Sang Gu;Kim, Woo Kyung;Jung, Jong Myung
    • Journal of Korean Neurosurgical Society
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    • v.65 no.4
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    • pp.539-548
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    • 2022
  • Objective : Although full-endoscopic lumbar interbody fusion (Endo-LIF) has been tried as the latest alternative technique to minimally invasive transforaminal lumbar interobody fusion (MIS-TLIF) since mid-2010, the evidence is still lacking. We compared the clinical outcome and safety of Endo-LIF to MIS-TLIF for lumbar degenerative disease. Methods : We systematically searched electronic databases, including PubMed, EMBASE, and Cochrane Library to find literature comparing Endo-LIF to MIS-TLIF. The results retrieved were last updated on December 11, 2020. The perioperative outcome included the operation time, blood loss, complication, and hospital stay. The clinical outcomes included Visual analog scale (VAS) of low back pain and leg pain and Oswestry disability index (ODI), and the radiological outcome included pseudoarthosis rate with 12-month minimum follow-up. Results : Four retrospective observational studies and one prospective observational study comprising 423 patients (183 Endo-LIF and 241 MIS-TLIF) were included, and the pooled data analysis revealed low heterogeneity between studies in our review. Baseline characteristics including age and sex were not different between the two groups. Operation time was significantly longer in Endo-LIF (mean difference [MD], 23.220 minutes; 95% confidence interval [CI], 10.669-35.771; p=0.001). However, Endo-LIF resulted in less perioperative blood loss (MD, -144.710 mL; 95% CI, 247.941-41.478; p=0.023). Although VAS back pain at final (MD, -0.120; p=0.586), leg pain within 2 weeks (MD, 0.005; p=0.293), VAS leg pain at final (MD, 0.099; p=0.099), ODI at final (MD, 0.141; p=0.093) were not different, VAS back pain within 2 weeks was more favorable in the Endo-LIF (MD, -1.538; 95% CI, -2.044 to -1.032; p<0.001). On the other hand, no statistically significant group difference in complication rate (relative risk [RR], 0.709; p=0.774), hospital stay (MD, -2.399; p=0.151), and pseudoarthrosis rate (RR, 1.284; p=0.736) were found. Conclusion : Relative to MIS-TLIF, immediate outcomes were favorable in Endo-LIF in terms of blood loss and immediate VAS back pain, although complication rate, mid-term clinical outcomes, and fusion rate were not different. However, the challenges for Endo-LIF include longer operation time which means a difficult learning curve and limited surgical indication which means patient selection bias. Larger-scale, well-designed study with long-term follow-up and randomized controlled trials are needed to confirm and update the results of this systematic review.