mengyun wu
225766148
Research on strategic adjustment of individuals affected by deep neighbors in a two layer network
Jie Lu Chunman Lu Mengyun Wu
225299650
Corporate governance mechanisms and corporate performance of firms in Nigeria and Ghana
PurposeThis study investigates the impact of corporate governance (CG) mechanisms with inclusion of compliance and diligence index on corporate performance (CP) of firms in Nigeria and Ghana. It further examines the moderating effect of financial distress on the relationship between CG and CP.Design/methodology/approachThe study used panel data of 102 nonfinancial listed firms of Nigeria and Ghana stock exchange for the period 2012 2016 with total observation of 510. The study first used OLS in estimating the influence of CG mechanisms on CP. Due to multicollinearity in the independent variables, ridge regression was employed.FindingsIt was revealed that ownership structure index and board compliance and diligence index, board size, board disclosure, ownership structure, shareholders' right and board compliance and diligence index had positive influence on ROA and ROE. Growth of Tobin's Q depends on board procedure and board compliance and diligence index. Also, financial distress (ZFS) negatively moderates the relationship between board structure index, board disclosure index, board procedure index, shareholders' right and performance (ROA and ROE) but negatively moderates between ownership structure index and Tobin's Q.Practical implicationsThis study provides interesting findings to policymakers in full implementation of CG codes as stated by OCED (2015) by West African firms with greater emphasis on compliance and diligence index since it positively influences all CP measures.Originality/valueThe study provides evidence of the importance of the introduction of the new index: compliance and diligence, which looks at disclosure of CSR activities. This has been overlooked by most researchers especially in Africa in assessing quality CG mechanisms.
Martha Coleman Mengyun Wu
222231632
Combination of Ant Colony Optimization and K nearest Neighbours: The Influence of Working Capital Management on Corporate Performance
Purpose: This study looked at the influence of working capital management on firm performance using both accounting measure (ROE) and market measure (Tobin's q) of firms listed in Nigeria and Ghana. Design/methodology/approach: The study used ant colony optimization (ACO) and k nearest neighbours (KNN) in establishing the long term effect of working capital management on corporate performance. Data were extracted from annual financial reports of non financial companies listed on the Nigeria and Ghana stock exchanges for the recession period 2012 2016, with a total observation of 510. Findings: ACO was applied to determine the working capital management variables that influence corporate performance, and KNN predicted its longitudinal influence, which, in our view, has not been deeply researched. It was discovered that non financial firms in the period of economic crises manage the account receivables and payables, as well as cash conversion cycles, maintaining optimum working capital for efficient operational activities. It is therefore assumed that these firms are exposed to external and other sources of finance, which enables them to increase investment in working capital, preventing the risk of low production hindering firms from settling debt, as well as customers, leading to the collapse of many firms in this region and accounting for an increase in the unemployment rate. Research limitations/implications: This study will inform corporate management and policymakers on the effect of economic crises on the performance of firms in the management of working capital to achieve desirable accounting and market performance. The ability of a firm to manage working capital during boom and recession periods enhances maximization of shareholders' wealth. Originality/value: This study will alert policymakers to the urgency in setting up appropriate policies to address pertinent issues regarding longitudinal influence of economic crises on firm continuity and value. JEL Code: M4
Martha Coleman Mengyun Wu
222081573
The Predictive Power of K Nearest Neighbor (KNN) The Effect of Corporate Governance Mechanisms on Earnings Management
This study investigates the long run effect of corporate governance mechanisms on earnings management of listed companies in Nigeria and Ghana. The study uses Ant Colony Optimization (ACO) and K Nearest Neighbor (KNN) in establishing a long run effect of good corporate mechanisms in reducing earnings management practice by corporate managers. ACO selected four major corporate governance mechanisms: Board Procedure Index, Board Disclosure Index, Ownership Structure Index, and Shareholders' Rights Index; these were the key corporate governance mechanisms that influence the reduction in earnings management activities. KNN produced a strong significant longitudinal effect of implementing good corporate governance mechanisms in decreasing the manipulating behavior of managers. Quality corporate governance mechanisms' implementation reduces the opportunistic behavior of corporate managers in manipulating earnings. Therefore, the study alert policymakers the urgency in setting up appropriate policies to enhance the reduction in earnings management practices to provide accurate financial information for stakeholders' financial decision making. The use of ACO and KNN in the study is a great novelty, which presents a calibration and prediction of the impact of corporate governance mechanisms on earnings management showing the rate of reduction.
Mengyun Wu Martha Coleman Jonas Bawuah
225286817
Successor selection in family business using theory of planned behaviour and cognitive dimension of social capital theory: evidence from Ghana
Succession of family enterprises has been an issue of concern to a number of researchers, and extensive studies have been conducted on this. Transfer of family business from one generation to next has resulted in collapse of most family business in both developed and developing economies. This study looked at succession in family enterprise in Ghana using theory of planned behaviour (Ajzen, 1991) and cognitive dimension of social capital theory to know the intention of founder/incumbent to hand over the family business to an internal successor.,Our target population for this study is family businesses run in Ghana, Western region. Ghana is not having statistical database on family businesses; therefore, the study relied on the database of registered SMEs which was gotten from Registrar General's Department, Ghana. This is the government department that is in charge of registering business in Ghana. A sample of 596 was used and received a response rate of 60% The study used structural equation model to find out how the variables correlate to discover the intention of the founder/successor on internal succession.,It was discovered that intention of founder/incumbent to hand over to an internal successor is predominantly determined by attitude, subjective norm, perceived behavioural control and cognitive dimension of the social capital. Trust does not influence the intention of founder/incumbent but attitude; this rejects the findings of most researchers.,Most family enterprises were not registered, which made it difficult to reach out to all family businesses. This limited the authors approach to only the registered family enterprises.,Family firms are the backbone of any economy, which comprise mostly of SMEs. Therefore, the understanding of succession by incumbents/founders as well as policymakers enhances firms' value and continuity.,The study was conducted in Africa, Ghana in particular, owing to the limited studies in this region.
Mengyun Wu Martha Coleman Abdul Rashid Abdul Rahaman Bless Kofi Edziah
225694837
An Empirical Analysis of Firm Specific Factors and Equity Premium: Evidence from Manufacturing Sector of Pakistan
Equity premium is a vital number in finance to be considered for making fund allocation and investment decisions. This study explores the relationship between (controllable) determinants of firm level equity premium in the context of Pakistan stock market. We use a sample of 306 firms' annual data, from 01/2001 to 6/2017, using a two stage least squares method to estimate our model. During the selected sample period, the average market premium of the Pakistan stock exchange (KSE100 Index) was twenty percent. The average equity premium of individual firms was only eight percent. Company fundamentals are considered determinants of firm level equity premiums. Panel data econometrics techniques were used to estimate the modified version of the multifactor model for the Pakistan Stock Exchange. It is found that the market premium, return on equity, dividend payout ratio, accounts receivable, and firm size significantly and positively affect the firm level equity premium. However, increase in the debt to equity ratio and quick ratio negatively affects that premium. The company fundamental variables are controllable for the firms and can be improved by company management to encourage investors and maximize shareholder wealth.
Mengyun Wu Muhammad Imran Linrong Zhang Qi He Allah Yar
222300183
Integrative functional linear model for genome wide association studies with multiple traits.
In recent biomedical research, genome wide association studies (GWAS) have demonstrated great success in investigating the genetic architecture of human diseases. For many complex diseases, multiple correlated traits have been collected. However, most of the existing GWAS are still limited because they analyze each trait separately without considering their correlations and suffer from a lack of sufficient information. Moreover, the high dimensionality of single nucleotide polymorphism (SNP) data still poses tremendous challenges to statistical methods, in both theoretical and practical aspects. In this article, we innovatively propose an integrative functional linear model for GWAS with multiple traits. This study is the first to approximate SNPs as functional objects in a joint model of multiple traits with penalization techniques. It effectively accommodates the high dimensionality of SNPs and correlations among multiple traits to facilitate information borrowing. Our extensive simulation studies demonstrate the satisfactory performance of the proposed method in the identification and estimation of disease associated genetic variants, compared to four alternatives. The analysis of type 2 diabetes data leads to biologically meaningful findings with good prediction accuracy and selection stability.
Biostatistics
Yanlin Li Fan Wang Mengyun Wu Shuangge Ma
210933894
Heterogeneous activation of persulfate by Ag doped BiFeO3 composites for tetracycline degradation.
Persulfate (PS) activation have been extensively considered as a promising technology for removing recalcitrant pollutants, due to their production of radicals with superior oxidation reactivity. However, a catalyst with high reactive and convenient recovery for PS activation still remains to be developed. In this work, the silver doped bismuth ferrite (Agx BiFeO3, x 0.1, 0.2, 0.3 and 0.4) catalysts with variable Ag content were synthesized via a facile sol gel method and applied as heterogeneous catalyst in PS activation for tetracycline (TC) degradation. Ag0.4 BiFeO3 presented the best catalytic activity compared with other Ag doped BiFeO3 composites, 91% TC could be efficiently removed within 60 min under optimized conditions and the reaction rate constant was 0.0338 min 1. On the basis of the characterization analysis and catalytic test results, Ag could be the effective active site in PS activation and had a significant effect on PS activation. Moreover, the initial pH has negligible effect on the catalytic performance, indicating that Ag0.4 BiFeO3/PS system could work in a wide pH range. The results of electron spin resonance spectroscopy and radical quenching tests suggested that both SO4 and OH radicals were involved in the Ag0.4 BiFeO3/PS system. The possible mechanism of Ag0.4 BiFeO3 activating PS and the major degradation pathway of TC degradation were proposed. At last, the reusability experiment results proved that Ag0.4 BiFeO3 catalyst still has a high catalytic performance after 4 times used.
Journal of colloid and interface science
Meng Xue Ouyang Xiaoming Li Qiuxiang Xu Ziletao Tao Fubing Yao Xiaoding Huang You Wu Dongbo Wang Qi Yang Zhuo Chen Zhoujie Pi
201617068
Baicalein and baicalin promote antitumor immunity by suppressing PD L1 expression in hepatocellular carcinoma cells.
Blocking the PD L1/PD 1 pathway to prevent the immune evasion of tumor cells is a powerful approach for treating multiple cancers, including hepatocellular carcinoma (HCC) Previous studies have shown that baicalein and baicalin are directly cytotoxic to some tumors, here we demonstrate that in addition to direct cytotoxicity, these two flavonoids stimulate the T cell mediated immune response against tumors through reduction of PD L1 expression in cancer cells. Interestingly, more significant tumor regression was observed in BALB/c mice than in BALB/c nu/nu mice after baicalein and baicalin treatment. PD L1 upregulation induced by interferon g (IFN g) was significantly inhibited by these two flavonoids in vitro. Both baicalein and baicalin enhanced the cytotoxicity of T cells to eliminate tumor cells, which was abrogated after HCC cells were transfected with a PD L1 overexpression plasmid or after T cells were pretreated with an anti PD 1 blocking antibody. Further mechanistic research indicated that the IFN g induced expression and promoter activity of PD L1 were suppressed by these two flavonoids, and these effects were mediated by STAT3 activity inhibition. Therefore, baicalein and baicalin decreased STAT3 activity, further downregulated IFN g induced PD L1 expression and subsequently restored T cell sensitivity to kill tumor cells. Our findings provide novel insight into the anticancer effects of baicalein and baicalin through which tumor growth is inhibited by PD L1 expression downregulation and suggest that these flavonoids have great potential for clinical treatment.
International immunopharmacology
Mengyun Ke Zhenhai Zhang Biyi Xu Shidi Zhao Yiming Ding Xiaoning Wu Rongqian Wu Yi Lv Jian Dong
202945781
Phase stability and microhardness of CoCrFeMnxNi2 x high entropy alloys
Abstract The phase stability of arc melted CoCrFeMnxNi2 x (x 0.25 1.75) high entropy alloys in as cast and 800 or 1000 degC annealed states were investigated using XRD, SEM, EDS, EBSD and DSC. A uniform FCC phase can be obtained in as cast CoCrFeMnxNi2 x (x 0.25 1.5) alloys. After being annealed at 1000 degC for 720 h, there was no phase changing in these alloys. However, after being annealed at 800 degC for 720 h, either the Cr rich BCC phase or the s phase will precipitate in the alloys with 10 15 at.%Mn or 25 30 at.%Mn, respectively. The precipitation has no orientation relationship with the FCC substrate. DSC test results indicate that the FCC phase is stable before melting and its transition point decreases with Mn content. The s phase is stable in the as cast and annealed CoCrFeMn1.75Ni0.25 alloy and will decompose at 1130 degC. Compared with the calculated phase diagram based on the TCFE thermodynamic database, it was confirmed that the calculation can predict the stability of the FCC phase well, but cannot predict the stability of the s or BCC phases. Moreover, microhardness test results indicate that long time annealing at 800 or 1000 degC has a limited effect on the microhardness of the FCC phase when the Mn content is below 25 at. However, precipitation of the s phase will greatly harden the CoCrFeMnxNi2 x (x 1.25, 1.5) alloys. These results will help to design the composition and treatment process of the Co Cr Fe Mn Ni high entropy alloys.
Journal of Alloys and Compounds
Mengyun Tian Ya Liu Jianhua Wang Xuping Su