46 research outputs found

    Foreign Ownership and Stock Return Volatility in Vietnam: the Destabilizing Role of Firm Size

    Get PDF
    This study aims to examine the relevance of foreign ownership to stock return volatility in the Vietnam stock market over ten years (2008 - 2017). After applying the fixed effects regressions and the extended instrumental variable regressions with fixed effects, we find that foreign ownership decreases the volatility of stock returns. However, the stabilizing impact of foreign ownership on stock return volatility becomes weaker in large firms since the coeffcient of the interaction term between firm size and foreign ownership turns out to be significantly positive. The estimated results remain robust when we use the future one-year volatility, other than the current one, as an alternative measure of the dependent variable

    Enantioselective separation of ofloxacin by ligand exchange chromatography

    Get PDF
    A ligand exchange HPLC method for enantioseparation of ofloxacin enantiomers was developed by a using C8 stationary phase. Chromatographic separation was performed on a Zorbax-300SB-C8 column eluted with the mobile phase consisting of 15 % methanol in water containing 10mM phenylalanin and 5 mM CuSO4 at flow rate of 0.8 mL/min. The method was simple, rapid and suitable for routine analytical studies of ofloxacin enantiomers

    Synthesis of new alkoxy substituted 4-piperidinobenzylidene malononitrile (PDCST) nonlinear optical chromophores

    Get PDF
    The new alkoxy-substituted 4-piperidinobenzylidene malononitrile (PDCST) nonlinear optical chromophores were synthesized for investigation into substitutional effect on electrooptic properties and response time. The concise four-step procedure afforded PDCST skeleton with various alkoxy-substituted groups such as methoxy, ethoxy and isobutoxy. Structures were confirmed by H, C-NMR and EI-MS spectroscopic analysis. Keywords. Nonlinear optical chromophores, 4-piperidinobenzylidene malononitrile (PDCST), bromination; formylation; Buchwald-Hartwing, Knoevenagel condensation

    Crystal structure of two <i>N</i>'-(1-phenyl-benzyl-idene)-2-(thio-phen-3-yl)acetohydrazides.

    Get PDF
    The synthesis, spectroscopic data, crystal and mol-ecular structures of two N'-(1-phenyl-benzyl-idene)-2-(thio-phen-3-yl)acetohydrazides, namely N'-[1-(4-hy-droxy-phen-yl)benzyl-idene]-2-(thio-phen-3-yl)acetohydrazide, C13H10N2O2S, (3a), and N'-[1-(4-meth-oxy-phen-yl)benzyl-idene]-2-(thio-phen-3-yl)acetohydrazide, C14H14N2O2S, (3b), are described. Both compounds differ in the substituent at the para position of the phenyl ring: -OH for (3a) and -OCH3 for (3b). In (3a), the thio-phene ring is disordered over two orientations with occupancies of 0.762 (3) and 0.238 (3). The configuration about the C=N bond is E. The thio-phene and phenyl rings are inclined by 84.0 (3) and 87.0 (9)° for the major- and minor-occupancy disorder components in (3a), and by 85.89 (12)° in (3b). Although these dihedral angles are similar, the conformation of the linker between the two rings is different [the C-C-C-N torsion angle is -ac for (3a) and -sc for (3b), while the C6-C7-N9-N10 torsion angle is +ap for (3a) and -sp for (3b)]. A common feature in the crystal packing of (3a) and (3b) is the presence of N-H⋯O hydrogen bonds, resulting in the formation of chains of mol-ecules running along the b-axis direction in the case of (3a), or inversion dimers for (3b). The most prominent contributions to the surface contacts are those in which H atoms are involved, as confirmed by an analysis of the Hirshfeld surface

    Some chalcones derived from thio-phene-3-carbaldehyde: synthesis and crystal structures.

    Get PDF
    The synthesis, spectroscopic data and crystal and mol-ecular structures of four 3-(3-phenyl-prop-1-ene-3-one-1-yl)thio-phene derivatives, namely 1-(4-hydroxy-phen-yl)-3-(thio-phen-3-yl)prop-1-en-3-one, C13H10O2S, (1), 1-(4-meth-oxy-phen-yl)-3-(thio-phen-3-yl)prop-1-en-3-one, C14H12O2S, (2), 1-(4-eth-oxy-phen-yl)-3-(thio-phen-3-yl)prop-1-en-3-one, C15H14O2S, (3), and 1-(4--bromophen-yl)-3-(thio-phen-3-yl)prop-1-en-3-one, C13H9BrOS, (4), are described. The four chalcones have been synthesized by reaction of thio-phene-3-carbaldehyde with an aceto-phenone derivative in an absolute ethanol solution containing potassium hydroxide, and differ in the substituent at the para position of the phenyl ring: -OH for 1, -OCH3 for 2, -OCH2CH3 for 3 and -Br for 4. The thio-phene ring in 4 was found to be disordered over two orientations with occupancies 0.702 (4) and 0.298 (4). The configuration about the C=C bond is E. The thio-phene and phenyl rings are inclined by 4.73 (12) for 1, 12.36 (11) for 2, 17.44 (11) for 3 and 46.1 (6) and 48.6 (6)° for 4, indicating that the -OH derivative is almost planar and the -Br derivative deviates the most from planarity. However, the substituent has no real influence on the bond distances in the α,β-unsaturated carbonyl moiety. The mol-ecular packing of 1 features chain formation in the a-axis direction by O-H⋯O contacts. In the case of 2 and 3, the packing is characterized by dimer formation through C-H⋯O inter-actions. In addition, C-H⋯π(thio-phene) inter-actions in 2 and C-H⋯S(thio-phene) inter-actions in 3 contribute to the three-dimensional architecture. The presence of C-H⋯π(thio-phene) contacts in the crystal of 4 results in chain formation in the c-axis direction. The Hirshfeld surface analysis shows that for all four derivatives, the highest contribution to surface contacts arises from contacts in which H atoms are involved

    A Systematic and Critical Review on the Research Landscape of Finance in Vietnam from 2008 to 2020

    Get PDF
    This paper endeavors to understand the research landscape of finance research in Vietnam during the period 2008 to 2020 and predict the key defining future research directions. Using the comprehensive database of Vietnam’s international publications in social sciences and humanities, we extract a dataset of 314 papers on finance topics in Vietnam from 2008 to 2020. Then, we apply a systematic approach to analyze four important themes: Structural issues, Banking system, Firm issues, and Financial psychology and behavior. Overall, there have been three noticeable trends within finance research in Vietnam: (1) assessment of financial policies or financial regulation, (2) deciphering the correlates of firms’ financial performances, and (3) opportunities and challenges in adopting innovations and ideas from foreign financial market systems. Our analysis identifies several fertile areas for future research, including financial market analysis in the post-COVID-19 eras, fintech, and green finance

    Awareness and preparedness of healthcare workers against the first wave of the COVID-19 pandemic: A cross-sectional survey across 57 countries.

    Get PDF
    BACKGROUND: Since the COVID-19 pandemic began, there have been concerns related to the preparedness of healthcare workers (HCWs). This study aimed to describe the level of awareness and preparedness of hospital HCWs at the time of the first wave. METHODS: This multinational, multicenter, cross-sectional survey was conducted among hospital HCWs from February to May 2020. We used a hierarchical logistic regression multivariate analysis to adjust the influence of variables based on awareness and preparedness. We then used association rule mining to identify relationships between HCW confidence in handling suspected COVID-19 patients and prior COVID-19 case-management training. RESULTS: We surveyed 24,653 HCWs from 371 hospitals across 57 countries and received 17,302 responses from 70.2% HCWs overall. The median COVID-19 preparedness score was 11.0 (interquartile range [IQR] = 6.0-14.0) and the median awareness score was 29.6 (IQR = 26.6-32.6). HCWs at COVID-19 designated facilities with previous outbreak experience, or HCWs who were trained for dealing with the SARS-CoV-2 outbreak, had significantly higher levels of preparedness and awareness (p<0.001). Association rule mining suggests that nurses and doctors who had a 'great-extent-of-confidence' in handling suspected COVID-19 patients had participated in COVID-19 training courses. Male participants (mean difference = 0.34; 95% CI = 0.22, 0.46; p<0.001) and nurses (mean difference = 0.67; 95% CI = 0.53, 0.81; p<0.001) had higher preparedness scores compared to women participants and doctors. INTERPRETATION: There was an unsurprising high level of awareness and preparedness among HCWs who participated in COVID-19 training courses. However, disparity existed along the lines of gender and type of HCW. It is unknown whether the difference in COVID-19 preparedness that we detected early in the pandemic may have translated into disproportionate SARS-CoV-2 burden of disease by gender or HCW type

    Prospects for Food Fermentation in South-East Asia, Topics From the Tropical Fermentation and Biotechnology Network at the End of the AsiFood Erasmus+Project

    Get PDF
    Fermentation has been used for centuries to produce food in South-East Asia and some foods of this region are famous in the whole world. However, in the twenty first century, issues like food safety and quality must be addressed in a world changing from local business to globalization. In Western countries, the answer to these questions has been made through hygienisation, generalization of the use of starters, specialization of agriculture and use of long-distance transportation. This may have resulted in a loss in the taste and typicity of the products, in an extensive use of antibiotics and other chemicals and eventually, in a loss in the confidence of consumers to the products. The challenges awaiting fermentation in South-East Asia are thus to improve safety and quality in a sustainable system producing tasty and typical fermented products and valorising by-products. At the end of the “AsiFood Erasmus+ project” (www.asifood.org), the goal of this paper is to present and discuss these challenges as addressed by the Tropical Fermentation Network, a group of researchers from universities, research centers and companies in Asia and Europe. This paper presents current actions and prospects on hygienic, environmental, sensorial and nutritional qualities of traditional fermented food including screening of functional bacteria and starters, food safety strategies, research for new antimicrobial compounds, development of more sustainable fermentations and valorisation of by-products. A specificity of this network is also the multidisciplinary approach dealing with microbiology, food, chemical, sensorial, and genetic analyses, biotechnology, food supply chain, consumers and ethnology
    corecore