MACRO-ZOOPLANKTON ABUNDANCE IN RELATION TO METAL ACCUMULATION AND WATER QUALITY IN TRUC BACH LAKE

Urban lake pollution is one of the serious issues due to suffering of waste discharged from householders. However, there is a gap of knowledge about the diversity of zooplankton species and how metals accumulate in zooplankton in urban ecosystems. We addressed this by determining the rule of blooming macro-zooplankton in Truc Bach lake and levels of two essential metals: copper (Cu), and zinc (Zn) and of three non-essential metals: arsenic (As), and lead (Pb) in water samples were determined. The results showed that Cladocerans and copepods are macro-zooplankton dominant species in Truc Bach Lake. Water temperature significantly affects the variety of copepod blooming. Arsenic concentration in water collected from the lake exceeded the safety level of current Vietnamese regulation. As concentration in macro-zooplankton positively correlated with metal concentrations in the water (p 0.05) while the concentration of Cu, Zn, and Pb in water has no significant correlation with the metal in zooplankton’s body. The relative abundance of adult copepods in Truc Bach lake had a negative correlation with As concentration in water (p = 0.01). The higher As concentration in water, the lower relative abundance of copepods was found in the sample

Do Corporate Social Responsibilities Support Its Financial Performance? Evidence of the Listed Firms in Vietnam

In the latest decades, corporate social responsibilities (CSR) are incrementally noticed in emerging countries regarding to the surge of globalization and the advance of social concerns. However, there exist opposing arguments on how CSR practices influence a firm’s financial performance (CFP), either in theoretical or empirical perspectives, causing many managers’ hesitation in CSR engagement. This study, therefore, examines the impacts of CSR on CFP, considering the individual effect of each CSR endeavor by using the data from listed firms’ financial statements during the period 2015-2019 and panel regression analysis methods. The findings reveal inconstant effects of different CSR activities on CFP. Specifically, a firm’s fulfillment of shareholders’ and customers’ interests contributes to raise its profitability, while its engagement in the benefits of employees and creditors causes a reduction in financial returns. Interestingly, the correlations between firms’ responsibilies towards regulators and suppliers and CFP are statistically insignificant. Furthermore, we make pairwise marginal comparisons to identify the distinctions of CSR-CFP relations across industries. The results only indicate that listed firms in Utilities sector have the lower level of CSR intensity than those in Consumer Discretionary and Consumer Staples sectors. The implications and limitations are also discussed in this study

Mediating Effect of Social Commerce Continuance Use Intention on the Relationship Between Perceived Values and Brand Loyalty

The purpose of this paper is to examine the mediating effect of social commerce continuance use intention on the relationship between perceived values and brand loyalty in the social commerce context. The data was collected from 176 members of the Apple Watch Social Commerce site in Vietnam via an online questionnaire. Applying the structural equation modelling method, we found that social commerce continuance use intention has mediating effects on the relationship between perceived values and brand loyalty. Keywords: Perceived values, continuance use intention, brand loyalty, social commerce, Vietnam DOI: 10.7176/EJBM/12-11-07 Publication date: April 30th 202

SOLUTIONS TO ENHANCE THE COMPETITIVE ADVANTAGE OF SMALL AND MEDIUM ENTERPRISES IN THE CONTEXT OF POST-COVID-19 PANDEMIC IN TRA VINH PROVINCE, VIETNAM

The purpose of this research is to find solutions to enhance the competitiveness of small and medium-sized enterprises in the context of the Post-Covid-19 pandemic in Tra Vinh Province, Vietnam, by collecting secondary data from reports from Tra Vinh Provincial People’s Committee, Tra Vinh Department of Planning and Investment, and Tra Vinh Provincial Statistics Office in the period 2016-2020. The authors used descriptive statistics, synthesis, analysis, evaluation, and expert surveys to verify former hypotheses about small and medium-sized enterprises and search for feasible solutions to enhance the competitiveness of small and mediumsized enterprises in Tra Vinh Province. The study analyzed the situation of small and mediumsized enterprises during the period 2016–2019 regarding the actual operation status, advantages, and limitations in the competition of Small and Medium Enterprises in Tra Vinh, Vietnam. From the research findings, the study proposes solutions to improve competitive advantages for Small and Medium Enterprises in Tra Vinh in the post-Covid-19 pandemic future

The Effect of Awareness on the Behavior of Advertisement on Social Network Basis for Cosmetic Products Line

The study examines the factors affecting the perception and interaction behavior with advertising cosmetic products. The authors used SPSS and Smart PLS software to conduct statistics and analyze survey results. The results of data analysis show that there are 5 factors that directly affect the perception of avoidance: Health concerns; Doubts about advertising intermediaries; Privacy concerns; Information value; Obstructing cognitive goals. The factor that directly affects Avoidant Behavior is Perception of avoidance, there are 5 factors that indirectly affect Avoidant Behavior: Health concerns; Doubts about advertising intermediaries; Privacy concerns; Information value; Obstructing cognitive goals. At the same time, the research also shows that negative experiences do not affect the impact process from Avoidant Perception to Avoidant Behavior. This study has important practical elements for businesses, managers and even social network users in reducing users' awareness and avoidance of advertising

Osteogenesis activity of fractions extracted from Clinacanthus nutans (Burm. F.) Lindau

Osteogenesis activity of fractions extracted from Clinacanthus nutans was evaluated on an in vitro model using osteoblast MC3T3-E1 cells. The results showed that all fractions, including ethanol (EtOH), n-hexane, ethyl acetate (EtOAc) and butanol (BuOH) were not significantly toxic to the osteoblast cells at the test concentrations of 5, 10, 25, and 50 µg/mL. The EtOH and EtOAc fractions exhibited the highest osteogenesis activity in terms of enhancement of alkaline phosphatase (ALP) and mineralization activity of MC3T3-E1 cells, especially the EtOAc fraction which increased ALP activity up to 30% and mineralization activity up to 100%. Thus, the EtOAc fraction shows osteogenesis activity through stimulating activites of the two markers for bone generation including ALP and mineralization in osteoblast cells. The fraction is now under extensive investigation to isolate and fully understand the modes of action of the active compounds. 

Does exporting spur firm productivity and promote inclusive growth? : evidence from Vietnam

Are exporting firms superior because only superior firms choose to become exporters or do they become superior by virtue of being exporters and having to face greater competition and to specialize in core activities? Findings show that the decision to export induces a gain in capital productivity for the new exporters, but no significant effect is observed for labour productivity and Total Factor Productivity (TFP). This result offers some support for the learning-by-exporting effect that occurs within a sector. Entry of Vietnamese firms into the world market can spur inclusive economic growth of the country

Using metagenomics tool to evaluate the enrichment efficiency of methanogens in marine sediment in Truong Sa archipelage, Khanh Hoa province, Vietnam

Methanogens (archaea bacteria that produce methan) play an important role in the anaerobic digestion of organic waste, however, in marine environment, the low density of methanogens makes anaerobic digestion very slow. In this study, we used methagenomics tool to evaluate the enrichment efficiency of methanogens communities in marine sediments as a basis for building a anaerobic microbial formulation to treat organic waste in marine environment. The results of determination of methanogen density by MPN method have shown that methanogen has been accumulated with higher density (up to 3.2.107 MNP/ml) through 2 times of enrichment in artificial seawater with CH3COONa 10 mM substrate. In addition, metagenomics data have also shown a decrease in the number of archaea species through each enrichment, indicating that methanogenic species have gradually dominated the microbial community. This is the first study on using metagnenomics tools to evaluate the enrichment of methanogens in marine sediment samples in Truong Sa archipelago, Vietnam. Metagenomics data help provide more reliable evidence in microbial studies, especially in obligate anaerobes such as methanogens

Effects of palladium on the optical and hydrogen sensing characteristics of Pd-doped ZnO nanoparticles

Abstract The effect of palladium doping of zinc oxide nanoparticles on the photoluminescence (PL) properties and hydrogen sensing characteristics of gas sensors is investigated. The PL intensity shows that the carrier dynamics coincides with the buildup of the Pd-related green emission. The comparison between the deep level emission and the gas sensing response characteristics allows us to suggest that the dissociation of hydrogen takes place at Pd Zn -vacancies ([Pd 2+ (4d 9 )]). The design of this sensor allows for a continuous monitoring in the range of 0-100% LEL H 2 concentration with high sensitivity and selectivity. 126

Influence of biofertilizer produced using drumstick (Moringa oleifera L.) unused parts on the growth performance of two leafy vegetables

The non-edible parts of Moringa oleifera, such as stems, branches or leaf petioles, have often been discarded while the leaves are consumed as a vegetable or are used to produce organic fertilizer. This study aimed to determine the optimal conditions for producing Moringa organic fertilizer (MOF) from previously unused parts and to compare these fertilizers with cow manure and bio-organic fertilizer. Seventy kilograms of the unused Moringa parts were blended with fifty kilograms of manure, 0.2 kilogram of Trichoderma-based product and two kilograms of superphosphate. The mixture was incubated at different intervals, including 5, 7 or 9 weeks. Next, the effects of MOF on the growth, yield, ascorbic acid content and Brix of lettuce and mustard spinach were also determined and compared with other organic fertilizers (cow manure and bio-organic fertilizer). Results of the study revealed that 25 tons per ha of MOF were significantly superior to those treated with cow manure and bio-organic fertilizer in the case of vegetable yields. Further, 7 weeks of MOF incubation was found suitable to produce an optimal yield during the various incubation period. These results suggested that the Moringa non-edible parts can make organic fertilizer and enhance growth, yield, and leafy vegetable production