Finding the best tour for travelling salesman problem using artificial ecosystem optimization

This paper presents a new method based on the artificial ecosystem optimization (AEO) algorithm for finding the shortest tour of the travelling salesman problem (TSP). Wherein, AEO is a newly developed algorithm based on the idea of the energy flow of living organisms in the ecosystem consisting of production, consumption and decomposition mechanisms. In order to improve the efficiency of the AEO for the TSP problem, the 2-opt movement technique is equipped to enhance the quality of the solutions created by the AEO. The effectiveness of AEO for the TSP problem has been verified on four TSP instances consisting of the 14, 30, 48 and 52 cities. Based on the calculated results and the compared results with the previous methods, the proposed AEO method is one of the effective approaches for solving the TSP problem

The mediating effects of switching costs on the relationship between service quality, customer satisfaction and customer loyalty: A study in retail banking industry in Vietnam

This paper develops and empirically tests the mediating role of switching costs in service quality - loyalty and satisfaction-loyalty relationships. Specially, different types of switching costs are tested separately providing more insights about their roles. This approach extended the insights on mediating effects of switching costs by differentiate the roles of positive switching costs and negative switching costs in the model. A research model about the interrelationships between service quality, customer satisfaction, switching costs and customer loyalty is developed. Based on this model, a survey is conducted with retail banking customers, with and 261 valid respondents. The hypotheses are then proposed and tested using Structural equation modeling technique (SEM). The analysis reveals that: positive switching cost is a significant mediator for both service quality-loyalty and satisfaction-loyalty relationships, while negative switching cost only mediates the service quality-loyalty relationship. These findings suggest that building and managing switching costs are necessary following-up steps after customer satisfaction for achieving long-term customer loyalty. However, using the right types of switching costs is necessary to significantly boost the loyalty from customers. © ExcelingTech Pub, UK

The Mediating Effects of Switching Costs on the Relationship between Service Quality, Customer Satisfaction and Customer Loyalty: A Study in Retail Banking Industry in Vietnam

This paper develops and empirically tests the mediating role of switching costs in service quality - loyalty and satisfaction-loyalty relationships. Especially, different types of switching costs are tested separately providing more insights into their roles. A research model about the interrelationships between service quality, customer satisfaction, switching costs and customer loyalty is developed. Based on this model, a survey is conducted with retail banking customers, with and 261valid respondents. The hypotheses are then proposed and tested using Structural equation modeling technique (SEM). The analysis reveals that: positive switching cost is a significant mediator for both service quality-loyalty and satisfaction-loyalty relationships, while negative switching cost only mediates the service quality-loyalty relationship. These findings suggest that building and managing switching costs are necessary following-up steps after customer satisfaction for achieving long-term customer loyalty

The effects of grouping types on promoting critical thinking in EFL collaborative writing

Nurturing critical thinking (CT) has been acknowledged as a core objective of tertiary education, and drawn attention from academia of teaching English as a Foreign Language (EFL), particularly in EFL argumentative writing. It has been claimed that collaborative learning which stimulates the active exchange of ideas within small groups not only increases interest among the participants but also promotes critical thinking. One of the important aspects of learning and teaching through collaboration is the group composition or grouping “who with whom”. The present study was an attempt to investigate the impact of homogeneous and heterogeneous groupings on critical thinking in collaborative writing. Having been required to write an argumentative essay as a pre-test, 75 participants, who were categorized by their prior critical thinking levels, were assigned into three group types: heterogeneous, homogeneous high and homogeneous low groups. As a consequence, four types of students were considered their improvement before and after the experiment: high-level students in heterogeneous groups, lowlevel students in heterogeneous groups, high-level students in homogeneous groups, low-level students in homogeneous groups. The results demonstrated that learners improved their critical thinking level through collaborative writing, whether working with stronger or weaker peers. However, heterogeneous grouping showed superiority over homogeneous grouping at the low level. The results revealed that cooperative learning could be especially beneficial for low students. It is hoped that the findings of the present study will give teachers deep insights into group compositions in collaborative learning courses, and will help them make better group experiences for students

The Distribution of Microplastics in Beach Sand in Tien Giang Province and Vung Tau City, Vietnam

Microplastics threaten the ecosystem because of undesirable properties such as non-biodegradability, easy-to-absorb persistant organic compounds, etc. They are found worldwide in marine, fresh water and beach sand environments. In this study, microplastics in beach sand samples from two sites in Tien Giang province and two sites in Vung Tau city were investigated. The results showed that the microplastics amount was 0 to 295 pieces/kg dry sand and they mainly distributed near estuarine areas. Microplastics were more prevalent at bathing sites than non-bathing sites. In Tien Giang fragments were the most dominant among the three types of shapes (fragments, fibers, granules) at 60.2%. In Vung Tau granules were most prevalent at 71.7%. The composition of the plastics was confirmed by Fourier-transform infrared spectroscopy. It was revealed that PE, PP and PS were the main types of plastics found in the sampling sites.

Income Diversification and Financial Performance: The Mediating Effect of Banks’ Size, Ownership Structure, and the Financial Crisis in Vietnam

Research aims: This study focuses on the correlation between income diversification and financial performance, taking into account banks’ size, type of ownership, and the financial crisis.Design/Methodology/Approach: This study uses financial data of 29 commercial banks in Vietnam during the period from 2005 to 2018. This research employs a Generalized Method of Moments (GMM) regression.Research findings: The results do not find statistical evidence of a direct effect of banks’ income diversification on their financial performance. However, when considering the classification factors, such as the bank’s size and ownership type, the findings show that big banks and state-owned banks could take advantage of diversification strategies to boost their profitability. Moreover, the study has proven that income diversification generates a significant positive effect on banks’ financial performance during the crisis time.Theoretical contribution/Originality: This study provides a theoretical evidence on the direct effect of income diversification on a bank’s financial performance concerning banks’ size, ownership type, and the financial crisis.Practitioner/Policy implication: Further, this research also offers the bank’s managers, policymakers, and investors an insight of good banks’ financial performance in the context of an unstable economy.Research limitation/Implication: The limitations still exist in this research, such as (1) the number of banks participating in the research sample was a predictable limitation; (2) this research mainly focused on financial variables but ignored the variables representing the managers’ behavior and the banks’ organizational structure; (3) the future studies can focus on these aspects to explore further the hidden picture of diversification strategy and banking performance

Highly-efficient electrochromic performance of nanostructured TiO2 films made by doctor blade technique

Electrochromic TiO2 anatase thin films on F-doped tin oxide (FTO) substrates were prepared by doctor blade method using a colloidal solution of titanium oxide with particles of 15 nm in size. The films were transparent in the visible range and well colored in a solution of 1 M LiClO4 in propylene carbonate. The transmittances of the colored films were found to be strongly dependent on the Li+ inserted charges. The response time of the electrochromic device coloration was found to be as small as 2 s for a 1 cm2 sample and the coloration efficiency at a wavelength of 550 nm reached a value as high as 33.7 cm2 C−1 for a 600 nm thick nanocrystalline-TiO2 on a FTO-coated glass substrate. Combining the experimental data obtained from in situ transmittance spectra and in situ X-ray diffraction analysis with the data from chronoamperometric measurements, it was clearly demonstrated that Li+ insertion (extraction) into (out of) the TiO2 anatase films resulted in the formation (disappearance) of the Li0.5TiO2 compound. Potential application of nanocrystalline porous TiO2 films in large-area electrochromic windows may be considered

Research on Factors Affecting Credit Risk of Joint Stock Commercial Banks on Vietnam Stock Market

Design/methodology/approach: The article aims at identifying factors affecting credit risk of commercial banks in Vietnam. The study uses data collected from financial statements of 15 typical joint stock commercial banks out of a total of 27 joint stock commercial banks listed on the Vietnam stock exchange from 2012 to 2022 with panel data of 15 joint stock commercial banks for the period 2012 - 2022. The banks in the research data are the those with the largest total assets in the banking system. After collecting and processing data, research sample includes 165 observations and the study uses E-view software in quantitative analysis to build a regression model to determine the relationship and level of influence of Internal factors to credit risk of listed joint stock commercial banks.   Findings: Research results indicate that factors affecting credit risk of listed joint stock commercial banks include: Ratio of equity to total assets, capital structure of the bank, and operational performance of the banks.   Research, Practical & Social impications: These results confirm the importance of taking into account micro finance factors when making financing. Understanding the impact of these factors and relationships contributes to decision and risk management.   Originality/value: In order to limit credit risk it is necessary to focus on: Ensuring reasonable equity; Stricter control over loan capital; Optimal use of resources

Isolation, screening antimicrobial activity and identification of fungi from marine sediments of the area Thanh Lan, Co To, Vietnam

Marine environment is rich in natural product resources, including marine microorganisms, especially fungi which are not only seen as a potential source of highly applicable bioactive substances but also can provide for science new chemical structures. The objective of this study is to isolate and screen fungal strains with antibacterial activity from the marine environment. Twenty five strains of fungi were isolated from marine sediments of Thanh Lan, Co To island and assessed on antibiotic activity against 7 tested microbial strains, including three Gram-negative bacteria (Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27853, Salmonella enterica ATCC13076), three Gram-positive bacteria (Enterococcus faecalis ATCC29212, Stapphylococus aureus ATCC25923, Bacillus cereus ATCC 13245), and the yeast Candida albicans ATCC10231. The minimum inhibitory concentration (MIC) against the tested microorganisms was determined for the crude extracts obtained from the culture broths after ethyl acetate extraction and vacuum rotary evaporation. Three strains with the highest antimicrobial activity M26, M30 and M45 were capable of inhibiting 4 - 5 of the 7 tested microorganisms with MIC values from 64 to 256 μg/ml, depending on each tested strain. Morphological and phylogenetic investigations based on 18S rRNA gene sequences of the three selected strains showed that strains M26 and M30 belonged to the genus Penicillium, whereas strain M45 belonged to the genus Neurospora. The sequences of 18S rRNA gene of three strains M26, M30 and M45 were registered on GenBank database with accession numbers: MH673730, MH673731, MH673732, respectively. Research results showed that marine environment has a great potential in isolation of fungal strains for the search for antibacterial substances as well as other biologically active compounds

Neoarchean and Paleoproterozoic K-rich granites in the Phan Si Pan Complex, north Vietnam : constraints on the early crustal evolution of the Yangtze Block

This study was financially supported by projects from the China Natural Science Foundation (41672222) and State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan (MSFGPMR201802). PAC acknowledges support from Australian Research Council grant FL160100168. This study was also supported by the Ministry of Natural Resources and Environment of Vietnam, Project BĐKH.29/16-20 to Dung My Tran.Precambrian igneous and metamorphic rocks of the Phan Si Pan Complex, North Vietnam, constitute the southern extension of the Yangtze Block, and provide a valuable record of the early evolution of the continental crust. We present results of U-Pb zircon geochronology and geochemistry for Precambrian granites in this complex to constrain their emplacement age and genesis. Granites from three plutonic bodies yielded ages of 2848 ± 15 Ma, 2768 ± 19 Ma and 1869 ± 30 Ma, which represent newly-recognized late Archean to Paleoproterozoic potassic granite plutonism in the southern Yangtze Block. The average εHf(t) values range from −6.2 to 0.1 for the 2.85–2.77 Ga granitic rocks and -13.1 to -9.2 for the ca. 1.86 Ga granitic rocks, with two-stage model ages of 3.64 to 3.20 Ga and 3.31 to 3.07 Ga, respectively, suggesting derivation from partial melting of Paleoarchean and Mesoarchean crust. The late Archean potassic granites exhibit high K2O, and high Sr/Y and (La/Yb)N ratios with negligible Eu anomalies, indicating derivation from melting of the thickened lower crust, which is inferred to have occurred in an active margin setting. The late Paleoproterozoic alkali feldspar granites are characterized by high FeOT/(FeOT + MgO)(0.96–0.99) and 10000∗Ga/Al (2.75–2.94) ratios, showing an affinity of A-type granite. These A-type granites exhibit flat chondrite-normalized HREE patterns and strong negative Eu anomalies, and low Sr/Y and (La/Yb)N ratios, corresponding to melting at a shallow depth, probably in a post-collisional extension setting. Comparison of the rock units and events recorded by the Phan Si Pan complex with other Archean to Paleoproterozoic complexes (Houhe, Dongchuan, Yudongzi, Douling, Zhongxiang and Kongling complexes) in the Yangtze Block indicate spatially distinct histories of crustal growth, and thus may reflect independent terranes. The ca. 1.86 Ga post-collisional magmatism, which succeeds a 2.0–1.9 Ga metamorphic event, is distributed throughout the Yangtze Block, including the Phan Si Pan Complex, suggesting assembly of the disparate terranes and final cratonization of the Yangtze Block overlaps with, and may be related to, assembly of the Nuna supercontinent.PostprintPeer reviewe