cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.14457/cu.the.2016.68
title: CORPORATE INCOME TAX PLANNING THROUGH REAL EARNINGS MANAGEMENT: EMPIRICAL EVIDENCE FROM THAILAND

description: This empirical research investigates the association between corporate income tax planning and real earnings management of listed companies in Thailand. It also examines the influences of firms’ multinational characteristic and tax loss carryforwards on the association between corporate income tax planning and real earnings management. The research samples are listed companies in the Stock of Exchange of Thailand (SET) during the period of 2011- 2014. In this research, corporate income tax planning is defined as the ability to lower the corporate income tax expenses without reducing the book income. Specifically, four real earnings management activities are explored: sales manipulation, overproduction, discretionary expenses reduction and the timing of asset sales. The research findings indicate the association between corporate income tax planning and real earnings management in which firms that engage in real earnings management to manipulate the income upward would undertake corporate income tax planning to mitigate the additional corporate income tax subsequent to the incremental income. The association between both variables is also found in the multinational firms that engage in real earnings management through the production and discretionary expenses cut manipulations; and in firms with tax loss carryforwards engaging in real earnings management through overproduction, discretionary expenses reduction and asset sales manipulation. The results remain unchanged with the robustness tests. Overall, this research is expected to provide an insight into multinational firms and firms with tax loss carryforwards with regard to corporate income tax planning and real earnings management; and also to contribute to more informed decision-making of investors who rely on the financial reports. Most importantly, it is hoped that the research findings would bring about change in the current tax law so as to discourage or minimize the exploitation of regulatory loopholes through corporate income tax planning.
DOI: 10.14457/cu.the.2016.69
title: Market segmentation and foreign price premium in The Stock Exchange of Thailand

description: Foreign share premium in Thai stock market has exhibited the downward trend during 2002 to 2014. This study attempts to explain this phenomenon by three hypotheses which are demand differential, information availability, and diversification benefit. The panel regression and cross-sectional regression are employed to account for variation of foreign share premium over time and across firms. The results of the study show that demand differential between foreign and domestic investors plays important role to explain foreign share premium. As foreign investors' demand for Thai stock is downward sloping, lower foreign room left relative to foreign ownership limit indicates higher foreign demand and higher foreign share premium for that stock. Moreover, foreign investors are likely to shift their investment from traditional foreign share on the Foreign Board to Non-Votiing Depository Receipt (NVDR) over time as it is a close substitute investment of domestic share for foreign investors. The existence of NVDR cause foreign investors' demand to become more elastic resulting in lower foreign share premium. Together with information availability hypothesis, foreign investors are interested to invest in larger firms and firms with more analyst coverages, via NVDR rather than foreign share on the Foreign Board, since they need not to concern about foreign ownership limit. Nevertheless, diversification benefit is the motive driven foreign investors to invest in domestic share on the Foreign Board. For any stock, if its return yields lower correlation with market portfolio return, it shows the higher diversification benefit and results in higher foreign share premium.
DOI: 10.14457/cu.the.2016.70
title: Pension strategy under volatility clustering

description: This research investigates the effect of volatility clustering on optimal asset allocation in a defined benefit pension scheme. Three models of volatility clustering, GARCH, GJR and EGARCH models, are examined. Model parameters are estimated using a time series of S&P500 returns while the optimal strategy is obtained using the numerical method to solve dynamic programming. The volatility-clustering parameters of GARCH models significantly influence the decision rules of choosing optimal weight. The first parameter adjusts how much volatility in the past affects present volatility, and the second parameter captures amplitude of the uncertainty. Meanwhile, asymmetric volatility in GJR and EGARCH models, captured by an additional parameter, put a focus on high volatility in negative returns. To study the behavior of optimal strategies under different models, Monte Carlo simulation is used to obtain the distribution of optimal weights and fund values in each model. Observing the distribution from different models show that the EGARCH model yields the most reasonable strategy and, unlike GARCH and GJR models, rarely gives extreme weight on risky assets. Subsequently, the optimal strategies are backtested to see which model gives the best outcome. The three models give the similar rate of return in backtesting using S&P500 returns data, but the optimal strategy assuming the EGARCH model has most conservative strategy which will be beneficial in the presence of a financial crisis.
DOI: 10.14457/cu.the.2016.71
title: Retail investors and industry-based style investing : evidence from the Stock Exchange of Thailand

description: This study investigates if retail investors in the Stock Exchange of Thailand pursue industry-based style investing using transaction data during 2004-2013. It finds the coordination in retail investor demand at the industry-level. In contrast to the prediction of the style investing model, retail investor industry demand is negatively related to past industry returns. No relationship between retail investor industry demand and subsequent industry returns is found across all time horizons. In addition, there is evidence that after choosing to invest in an attractive industry, retail investors prefer to invest in small-cap stocks more than large-cap stocks. These findings suggest that retail investors' investment decisions are influenced by industry-wide categorization, and they make their buying decisions follow a two-step decision-making process.
DOI: 10.14457/cu.the.2016.72
title: The impact of attention on investors : evidence from the Stock Exchange of Thailand

description: This paper examines the influence of attention on three investor groups: individual investors, institutional investors and foreign investors in the setting of the Thai stock market between 2011 and 2014. To measure the impact of attention I sort stocks by their extreme daily returns and by their abnormal trading volume on a certain day. Purchasing stocks that grabbed ones attention earlier is a way to deal with the problem of having to choose from thousands of stocks that one could potentially buy. I test and confirm the hypothesis that individual investors are net buyers of attention grabbing stocks. Furthermore I hypothesize that attention affects different investor groups to a different degree in their buying behavior. I confirm that individual investors engage the most in attention driven buying behavior. Surprisingly I find strong evidence for attention driven buying behavior for institutional investors as well. Foreign investors merely show tendencies for purchases driven by attention grabbing stocks.
DOI: 10.14457/cu.the.2016.73
title: Identifying synergy in vertical merger and acquisition : the synthetic firm method

description: This research investigates the completed vertical merger and acquisition during 1998-2010 in five year windows both of before and after merger and acquisition whether the synergy demonstrates through the abnormal return and operating performance during the study period. According to this research, I exploit a new approach in which the most similarity of firm affects the return of firms: one set of the firm requires the actual merger and acquisition deals, while the other set requires the synthetic of the actual merger and acquisition deals. In this paper uses two model to demonstrate the existing of synergy and confirm that it can add more value to the acquirers. The results demonstrate the significantly negative abnormal return and the performance of the actual vertical merger and acquisition firms after making merger and acquisition deal. The results also examine the dark side of the merger and acquisition which relate to the conflict of interest between shareholders and their managers.
DOI: 10.14457/cu.the.2016.74
title: Value of cash during downturn

description: This study investigates the value of cash holdings among Asian firms: Thailand, The Philippines, Taiwan and Indonesia, which were affected by 1997 Asian financial crisis. Moreover, firms from Australia and New Zealand are analyzed as a comparison. For 3,717 firms from 6 countries between 1991and 2005, the findings indicate that the 1997 Asian financial crisis has impact on firms in Asian countries. Firms’ cash holdings do not contribute more to the value of firms during crisis period. Furthermore, the high level of cash has the same impact on firm value between crisis and non-crisis period. Although firms do not gain advantage from cash holdings, they do not lead things getting worse. Indeed, the findings lend support to free cash flow theory. After examining the investment rates among high cash Asian firms, the findings indicate that investment rates among high cash Asian firms are lower than low cash Asian firms during post-crisis period (i.e., recovery period). Moreover, the findings from examining the recovery rates (market valuation, dividend payout and return on assets) indicate that the market valuation of high cash Asian firms is not different from those low cash Asian firms during recovery period. However, high cash Asian firms are likely to pay dividends higher than those low cash Asian firms during pre-crisis period (i.e., normal period) and these patterns remain even after affected by the 1997 Asian financial crisis. For profitability (return on assets), high cash firms are not different in utilizing the assets to generate profit comparing to those low cash firms during recovery period.
DOI: 10.14457/cu.the.2016.75
title: Investor types and trading of the environment, social and governance stocks in the Stock Exchange of Thailand

description: This study involves finding how the Environmental Social and Governance (ESG) or the Corporate Social Responsibility (CSR) affects investors’ attention in the Stock Exchange of Thailand. The goal is to examine whether there is any interest in investing on the companies with good ESG or CSR practice in the Stock Exchange of Thailand (SET) represented by those in the Environment Social and Governance 100 (ESG100) list by Thaipat Institution or in the Thailand Sustainability Investment (TSI) list by SET, announced during 2014-2015. Conducting an event study, upon examination of these events, the result shows that there are significantly negative abnormal returns of the TSI list. On the other hand, there are less significantly negative for the abnormal returns after announcement for the ESG100 list. As the result of CAAR is very economically small for daily and yearly returns, investors are unlikely to be able to exploit the abnormal returns for trading strategy. In addition, this research study further examines which types of investors are more concerned about the companies advocating for CSR and finds that foreign investors concern more CSR stocks than institutional investors and institutional investors concern CSR stocks less than individual investors but there are no significant comparing foreign investors with individual investors for the method that uses percentage of buy and sell to compute trade imbalance, while there is no significant difference across investor types for trade imbalance calculated using levels of buy and sell method.
DOI: 10.14457/cu.the.2016.76
title: Effect of low level laser stimulation on salivary gland function in diabetic patients with hyposalivation

description: Saliva plays several functions and the most important roles among of those are the lubrication and the protection by defensive proteins. Salivary gland hypofunction showed a high prevalence in patient with diabetes. Previous studies indicated that protein mucin 5B concentration, which is important to lubrication, tended to decrease in hyposalivation patients and a decrease in histatin 5 was found in disease with fungal infection. The several previous studies indicated that low level laser therapy (LLLT) can stimulate salivary gland function with an increase in salivary flow rate in systemic disease patients with dry mouth complication. Therefore, LLLT may be applied as the treatment choice for patients with dry mouth symptom. This study aimed to investigate the effect of low-level laser stimulation on salivary gland function in diabetic patients with hyposalivation. The assessment of salivary flow rates, mucin 5B (MUC5B), mucin 7 (MUC7), histatin 5 concentrations, and questionnaires were performed. A total of twelve diabetic patients under criteria set in this study at Bangkok Hospital were participated on a voluntary basis. A low power laser was used to stimulate major salivary glands with an irradiation time of 40 s on 6 occasions (3 times in 2 consecutive weeks). Questionnaire related to dry mouth symptoms were given. Salivary flow rates and questionnaire were assessed as well as MUC7, MUC5B, and histatin 5 protein concentration in saliva at the 1st visit, 6th visit, and 6th week follow-up visit. The unstimulated salivary flow rate and MUC5B concentration at the 6th week follow-up visit were significantly increased compare with at the 1st visit. By contrast, the concentration of histatin 5 exhibited a significant decrease at the 6th week follow-up visit compare with at the 1st visit . The mean dry mouth score revealed a significant decrease regarding to dry mouth symptoms at the 6th visit and 6th week follow-up visit compared with at the 1st visit. The correlation between overall dry mouth score and flow rate showed the strongest positive correlation at the 6th visit. There were no significant differences found on stimulated salivary flow rate and MUC7 concentration. Our results indicate a beneficial effect of LLLT on diabetic patients in increasing salivary flow rate and maintaining oral lubrication.
DOI: 10.14457/cu.the.2016.77
title: WHITENING TOOTHPASTE EFFECT ON GLOSS, SURFACE ROUGHNESS AND COLOUR STABILITY OF PROVISIONAL RESTORATIVE MATERIALS

description: Purpose: This study was to evaluate the effect of whitening toothpaste on gloss, surface roughness, and colour stability of provisional restorative materials. Material and Methods: Three provisional restorative materials were evaluated; Unifast Trad (UT), Protemp4 (PT) and TelioC&B (TC). One direct composite resin, Filtek Z250XT (FT), was chosen as control. Two toothpastes, Colgate Optic Whitening® (CO), and Colgate Proven Cavity Protection® (CP), and deionized water (DI) without toothpaste were selected as the brushing media in this study. Gloss, surface roughness, and colour were measured before and after 10,000 (10k) brushing cycles with each brushing media. One-way ANOVA was used to analyze the gloss change (∆G), surface roughness change (∆Ra), and colour change (∆E) of each material with all brushing media. Results: FT, TC and UT showed significant decrease in gloss after brushing with CO. Only PT did not show significant difference in gloss after brushing with all media. All materials showed significant increase in Ra after brushing with CO. No significant difference in ∆E were observed in all materials except TC which showed significant change in ∆E after brushing with CO compared to DI. Conclusion: Brushing with whitening toothpaste (CO) caused significant reduction in gloss of all materials except bis-acryl composite resin (PT) and significant increase in surface roughness of all materials when compared to DI. ∆E of all materials, after brushing with all media, were within 50/50% acceptability threshold (∆E &lt;2.7).
DOI: 10.14457/cu.the.2016.78
title: Oral epithelial-derived mediators suppress RANKL expression in human mandibular-derived bone cells

description: Prostaglandin E2 (PGE2) accumulates in inflamed periodontal tissue and induces RANKL/RANK/OPG signaling associated with bone resorption. Although oral epithelial cells maintain tissue homeostasis, the role of oral epithelial cells in RANKL regulation remains unknown. To investigate the epithelial mediators involved in regulating RANKL expression in PGE2-stimulated human mandibular bone-derived cells (HMBCs) and RANKL driven osteoclastic-cell activity. HMBCs were stimulated with 0.1 μM PGE2 for 24 h to increase RANKL expression. Concurrently, cells were treated with epithelial supernatant containing constitutively released or P.gingivalis Lipopolysaccharide (PgLPS)-stimulated epithelial mediators, or recombinant IFN-γ. Some cells were pretreated with an anti-IFN-γ antibody before PGE2 stimulation. The expression of RANKL, OPG, and inflammation-related cytokines was assessed by quantitative PCR, and proteins levels were evaluated by ELISA and western blot. THP-1 human monocytes and HMBCs were cocultured to determine the ability of HMBCs to drive THP-1 differentiation into osteoclast-like cells. Osteoclast function was determined using a bone resorption pit assay. PGE2 significantly increased RANKL mRNA expression and RANKL protein in HMBCs dose-dependently, however, the OPG protein levels remained similar. Epithelial cells constitutively released IFN-γ, which was substantially increased by PgLPS. HMBCs treated with epithelial supernatant or recombinant IFN-γ, concurrently with PGE2 stimulation, reduced RANKL, but not OPG, expression similar to baseline. In contrast, the anti-IFN-γ antibody reversed the effect of the epithelial mediators on RANKL expression. THP-1 osteoclast activity increased when cocultured with PGE2-stimulated HMBCs. However, epithelial-derived IFN-γ decreased PGE2-induced RANKL expression in HmBCs, resulting in decreased THP-1-derived osteoclast activity. PGE2 stimulation significantly increases RANKL expression in HMBCs. However, recombinant IFN-γ, or IFN-γ derived from oral epithelial cells, suppresses RANKL expression at both the mRNA and protein level. Therefore, oral epithelial cells, by releasing IFN-γ, suppress RANKL upregulation in HMBCs and reduce osteoclast activity.
DOI: 10.14457/cu.the.2016.79
title: Fracture resistance of various restorations for endodontically treated teeth caused from abfraction

description: The aim of this study was to evaluate fracture resistance and failure pattern of endodontically treated premolars with simulated abfraction in various restorations. Thirty-two extracted two-rooted maxillary first premolars with same sizes and shapes were randomly divided into 4 groups (n=8) for different restorations types. The control group was endodontically treated without simulated abfraction and restored with resin composite at access opening. Groups 1 - 3 were simulated with abfraction, filled with resin composite, endodontically treated and then restored with different methods. Group 1 (RF) was restored with resin composite at access opening, group 2 (P/RF) was restored with fiber post and resin composite and group 3 (P/ZC) was restored with fiber post, resin composite and zirconium crown. The teeth then were placed into acrylic blocks with simulated PDL. The specimens were loaded at central fossae, 30° to long axis of the teeth until failure. The data were analyzed by one-way ANOVA and Scheffe test at a 95% level of confidence. The results showed that the fracture resistance of control group, groups RF and P/RF had not statistically significant difference (p&gt;0.05), while the fracture resistance of group P/ZC was significantly higher than those of groups RF and P/RF (p&lt;0.05) with no significant difference from control group. For failure patterns, 80% of specimens in control group, groups RF and P/RF failed with palatal cusp fractures, while all specimens in group P/ZC cracked and fractured along crown margins and posts retained crowns to roots. The study concluded that resin composite filling at simulated abfraction could present the fracture resistance close to the teeth without abfraction. The fiber posts did not affect fracture resistance of the teeth with simulated abfraction, however, they retained the crowns to the roots which prevented sudden coronal crown lost. The zirconium crowns and fiber posts could significantly increase fracture resistance of teeth with simulated abfraction. In addition, the coronal remaining walls at the cervical areas are the main factors for proper restorations.
DOI: 10.14457/cu.the.2016.80
title: Study of ALU methylation levels in various passages of human dental pulp stem cells

description: Human dental pulp stem cells (DPSCs) which can be isolated from pulpal tissue of tooth are being recognized as an alternative source of stem cells for cell-based therapies and tissue engineering. The replicative senescence which results in the alteration of regeneration and differentiation potential is an obstacle encountered during DPSCs culture in vitro. Although both genetic and epigenetic mechanism was found participating in the aging processes, the study in epigenetic mechanisms that involved with these biological processes of DPSCs is still very limited. Methylation level of Alu, an epigenetic alteration, was reported to be associated with human aging. In this study, the methylation level of Alu in different passages of DPSCs was studied by combined bisulfite restriction analysis. Moreover, the morphology and proliferation ability of human DPSCs were observed in every passages. We found that DPSCs in late passage showed replicative senescence, morphological change and had significant lower Alu methylation level than early passage. Our results suggest that Alu methylation level may involve in replicative senescence of DPSCs. Further study should be performed to clarify the mechanism controlling senescence of DPSCs in order to properly manipulation of DPSCs in therapeutic use.
DOI: 10.14457/cu.the.2016.81
title: BASIC FIBROBLAST GROWTH FACTOR REGULATES THE DIFFERENTIATION ABILITY OF STEM CELLS ISOLATED FROM HUMAN EXFOLIATED DECIDUOUS TEETH

description: The basic fibroblast growth factor (bFGF) play a crucial role in various biological processes, including cell growth, survivor, migration and differentiation in several types of stem cells. In this dissertation was focusing particularly on stem cells from human exfoliated deciduous teeth (SHEDs). SHEDs exhibited fibroblast-like morphology and express mesenchymal stem cell surface markers. These cells were able to differentiate into various lineages, including osteogenic, adipogenic, and neurogenic lineages. First, the roles of bFGF in dental tissue-derived mesenchymal stem cells were reviewed. The evidences suggest that bFGF regulate stem cell behaviors may depend on several factors, including dose, exposure time and cells type. Second, roles of endogenous bFGF on cell proliferation and osteogenic differentiation were revealed. bFGF knockdown and chemical inhibition of fibroblast growth factor receptor led to the reduction of colony forming unit and the increase of osteogenic differentiation potency. Third, the effect of bFGF on stemness maintenance in SHEDs was examined. bFGF promoted a pluripotent marker, REX1, gene expression in SHEDs. The bFGF-induced REX1 expression was occurred via FGFR and Akt signaling pathway. In addition, the results demonstrated the participation of interleukin-6 in bFGF-induced REX1 expression. Together, these evidences support the influence of bFGF in the maintaining of stemness and controlling of differentiation ability toward osteogenic lineage in SHEDs.