IMPROVING PROFITABILITY OF INTEGRATED RICE-SHRIMP FARMING IN BRACKISH AREA: A CASE STUDY OF MEKONG DELTA, VIETNAM

Rotation between rice and shrimp farming by way of filter ponds and diversification of farm activities was studied with the aims of testing the efficiency of filter ponds and evaluating the combination of incorporating the growing of upland-crops on dikes of rice fields. Three groups of farmers participated in study trials which were the pilot group used a filter pond and applied new methods, the control group had a filter pond and applied the recommended new methods, and the normal practice (control) group not having a filter pond. Results showed that the rice-shrimp farming system using a filter pond improved water quality (pH, alkalinity and salinity) and reduced input costs. Growing upland crops on the dikes had a high financial return; though for both vegetables and the grass for the dairy cows will strongly depend on the market. On one hectare of land, farmers using a filter pond for rice-shrimp farming combined with upland-crops had a higher economic return than the traditional rice-shrimp farming system (2,812 compared with 854 USD/ha/year). However, implementing this model requires farmers to build filter ponds to aid freshwater storage, proper management skills and family labour resources. Diversification of farm activities such as integrated rice-shrimp culture may be a strategy for farmers for adapting to the impacts of climate change such as extreme weather events, less rain and saltwater intrusion

Reproductive biology of sagor catfish (Hexanematichthys sagor Hamilton, 1822) in Can Gio water, Vietnam

835-840Sagor catfish (Hexanematichthys sagor Hamilton, 1822) is one of the most popular fish caught in Can Gio reserve biosphere. A study on reproductive biology was conducted to evaluate the reproductive parameters, including male–female distinction, gonadal development stages, sex ratio, spawning season, fecundity, and size at first sexual maturity. The results showed that the number of males and females in the nature was not significantly different. Male and female fish can be distinguished when they reach the mature size. Gonadal of the fish pass through five stages of maturation. The histological screening of gonad, percentage of maturation stage and gonadal somatic index value of the fish showed all year round spawning with a peak of spawning female from March to August. The length at first sexual maturity of the fish is 25.39 cm. Fecundity ranged from 60 to 145 ovaries/individuals strongly related to weight and length. The current findings provide the scientific foundation for the purpose of fishery resource management and artificial breeding of the blue sagor catfish

ASSESSMENT OF THE CURRENT SITUATION OF TOURISM DEVELOPMENT IN MANG DEN TOWN, KON PLONG DISTRICT, KON TUM PROVINCE, VIETNAM

This study surveyed 120 domestic tourists in Mang Den Town, using the convenience sampling method. The method used to analyze primary data was descriptive statistics. The research results have proposed six factors to evaluate the current situation of tourism development in Mang Den Town, Kon Plong District, Kon Tum Province, Vietnam including: (1) Quality of tourism services and tourism resources; (2) Perceived prices; (3) Human resources; (4) Security, order, and safety; (5) Quality of tourism services and tourism infrastructure; (6) and Tourism resources and perceived prices, in which "Human resources" is the factor that has the strongest impact on the current situations of tourism development in Mang Den Town. Through research results, the article has proposed some solutions to develop tourism in Mang Den Town more effectively in the future.  Article visualizations

Impact of Fintech’s Development on Bank Performance: An Empirical Study from Vietnam

In recent years, fintech has exploded in popularity and importance in the finan- cial industry. Its impacts have spread widely throughout the world, including Vietnam. This study aims to investigate the effect of fintech’s development on bank performance in Vietnam. Based on the unstructured data about fintech on the financial expert web- sites from Vietnam, the word frequency statistic technique of the text mining approach is applied for measuring fintech’s development under the support of Python-based solu- tions. The bank-level data of 15 Vietnamese banks for the period from the first quarter of 2019 to the second quarter of 2021 are collected from the quarterly financial statements in the Vietstock organization. Python programming and text mining techniques are used to compile this dataset by gathering information from popular and relevant websites. The generalized least squares method is used for estimating the panel models. The estimation result shows the significant impact of fintech’s development on bank profitability, but the net interest margin does not associate with the fintech variable. Besides, some interesting findings are revealed: The slow banking transformation to adapt to the rise of fintech and the COVID-19 pandemic increased bank profitability. Furthermore, suggestions for the banks and fintech companies are recommended, and the limitations and directions for further research are also proposed

Functionals of order statistics and their multivariate concomitants with application to semiparametric estimation by nearest neighbours

This paper studies the limiting behavior of general functionals of order statistics and their multivariate concomitants for weakly dependent data. The asymptotic analysis is performed under a conditional moment-based notion of dependence for vector-valued time series. It is argued, through analysis of various examples, that the dependence conditions of this type can be effectively implied by other dependence formations recently proposed in time-series analysis, thus it may cover many existing linear and nonlinear processes. The utility of this result is then illustrated in deriving the asymptotic properties of a semiparametric estimator that uses the k-Nearest Neighbour estimator of the inverse of a multivariate unknown density. This estimator is then used to calculate consumer surpluses for electricity demand in Ontario for the period 1971 to 1994. A Monte Carlo experiment also assesses the effi- cacy of the derived limiting behavior in finite samples for both these general functionals and the proposed estimator

Functionals of order statistics and their multivariate concomitants with application to semiparametric estimation by nearest neighbours

This paper studies the limiting behavior of general functionals of order statistics and their multivariate concomitants for weakly dependent data. The asymptotic analysis is performed under a conditional moment-based notion of dependence for vector-valued time series. It is argued, through analysis of various examples, that the dependence conditions of this type can be effectively implied by other dependence formations recently proposed in time-series analysis, thus it may cover many existing linear and nonlinear processes. The utility of this result is then illustrated in deriving the asymptotic properties of a semiparametric estimator that uses the k-Nearest Neighbour estimator of the inverse of a multivariate unknown density. This estimator is then used to calculate consumer surpluses for electricity demand in Ontario for the period 1971 to 1994. A Monte Carlo experiment also assesses the effi- cacy of the derived limiting behavior in finite samples for both these general functionals and the proposed estimator

Multifactorial Evolutionary Algorithm For Clustered Minimum Routing Cost Problem

Minimum Routing Cost Clustered Tree Problem (CluMRCT) is applied in various fields in both theory and application. Because the CluMRCT is NP-Hard, the approximate approaches are suitable to find the solution for this problem. Recently, Multifactorial Evolutionary Algorithm (MFEA) has emerged as one of the most efficient approximation algorithms to deal with many different kinds of problems. Therefore, this paper studies to apply MFEA for solving CluMRCT problems. In the proposed MFEA, we focus on crossover and mutation operators which create a valid solution of CluMRCT problem in two levels: first level constructs spanning trees for graphs in clusters while the second level builds a spanning tree for connecting among clusters. To reduce the consuming resources, we will also introduce a new method of calculating the cost of CluMRCT solution. The proposed algorithm is experimented on numerous types of datasets. The experimental results demonstrate the effectiveness of the proposed algorithm, partially on large instance

Chemical Constituents and Bacterial Activity of Essential Oils of Five Wax Apples (Syzygium samarangense) from Dong Thap Province, Vietnam

In the present study, essential oils from the leaves of five varieties of wax apple trees, (\u27An Phuoc\u27, \u27Hoa An\u27, \u27Hong Dao\u27, \u27Sua\u27, and \u27Xanh Duong\u27) collected in Dong Thap Province, Vietnam were isolated using hydrodistillation, and their constituents were for the first time identified via gas chromatography - mass spectrometry. A total of 74 compounds from essential oils were identified. These compounds were classified into four clusters by hierarchical clustering analysis. The main constituents of the essential oils isolated from the leaves of five varieties of wax apple trees were o-cymene, α-cubebene, epizonarene, β-gurjunene, and α-selinene. The antibacterial activity of the essential oils isolated from the leaves of five varieties of wax apples were evaluated for the first time. The results showed that the essential oils could inhibit the growth of four tested microorganisms: Bacillus cereus, Escherichia coli, Salmonella enteritidis and Staphylococcus aureus