In recent years, there have been great attentions in microbial fuel cells (MFCs) because they use a variety of biodegradable substrates as fuel and MFC is considered as a renewable energy source. However, MFC generates a very low power. Consequently, harvest and use of this energy source is still a major challenge for scientists. Thus, energy harvesting systems are very necessary for real applications. There have been many researches on technology to harvest and store energy from MFC, but they are only individual research projects. Therefore, this paper provides an overview of MFC energy harvesting technology and mentions the ability to develop into commercial energy source.

Fenobucarb has been widely used to control insects in rice paddy fields. This insecticide is shown to pose toxic effects on aquatic animals due to its inhibition on the normal activity of cholinesterase. This study aimed to isolate, screen and identify indigenous bacteria capable of degrading fenobucarb in the rice paddy soils. Twenty bacterial isolates able to grow on minimal medium supplemented with fenobucarb 100 mg/L as sole carbon source were isolated from eight soil samples collected from rice paddy soils of Co Do and Vinh Thanh district, Can Tho. Two isolates CĐ5.2 and CĐ5.3 obtained from Co Do fields showed the higher fenobucarb degradation with the efficiency of 58.2% and 60.1%, respectively, after nine days of incubation. Based on 16S-rRNA gene sequence analysis and biochemical characterization including activities of gelatinase, urease, oxidase, citrate assimilation and sugar fermentation, isolates CĐ5.2 and CĐ5.3 were genetically identified as Burkholderia arboris CĐ5.2 and Micrococcus terreus CĐ5.3, respectively.

The study focus on proper design and operation parameters of high-performance adhesion growth processes to treat aquatic products processing wastewater. With the organic loading rate of 2.06 g BOD/ m2.day-1 (based on biofilm area), 5-hour hydraulic retention time, after being treated with the three-stage rotating biological contactor and 30-minute static sediment, all effluent concentration of COD, BOD5, N-NH4+, TP, SS were met the discharge standard of QCVN 11-MT:2015/ BTNMT (column A). When operating with the organic loading rate of 2.4 g BOD/ m2.day-1, the hydraulic retention time of 4 hours, the effluent concentration of COD, BOD5, N-NH4+, TP, SS were reached column A of the standard of QCVN 11-MT:2015/BTNMT, while TP was 10.83 mg/L only reached column B of the standard. Thus, the three-stage aerobic rotating biological contactor can be used to treat aquatic products processing wastewater reaching column A of the QCVN 11-MT:2015/ BTNMT at 5-hour retention time, and loading organic matter is 2.06 g BOD/m2.day-1.

The study was conducted with the goal of establishing a database of poisonous plants in Ninh Kieu district, Can Tho city. A field research and survey method were used to follow 9 routes with 6 types of habitats in 10 months. Total 62 species of poisonous plants were found in the study area belonging to 2 divisions, 26 families and 52 genera of which, 31 species were not recorded in the list of “Cây độc ở Việt Nam” (Poisonous plants in Vietnam) by Tran Cong Khanh and Pham Hai (2004). Poisonous plants in the study area have the number of herbaceous species accounting for the highest proportion (43,55%); most of the toxins are in whole plants (accounting for 35,48%); vomiting and diarrhea are the most common symptoms of ingestion (50% and 45,16%, respectively). The main group of toxic substances are alkaloid, glycoside (accounting for 25,81%), fatty oil, triterpene, calcium oxalate (accounting for 11,29%).

The random state transition of stock price process will be modeled by a hidden Markov model. This model based on a pair (Xh,Kh) of stochastic processes. The process (Xh,) is called the state process, a hidden Markov chain, which represents the random state transition of stock price process. The observation process (Kh) represents the measured sequence of stock price. The parameters of the model were estimated from the real data using maximum likelihood estimation via expectation-maximization algorithm (EM algorithm). Forecast for stock price sequence using simulation data is the proposed application.

The aim of this paper is to study the model of diffusion process in one dimension. The method of moments is used, as in Depauw and Derrien (2009) and Chuong (2014) to prove that this process converges in distribution to a normal law (Theorem 1.1). More precisely, with be the corresponding infinitesimal generator of the previous process and a given function f, we solve the Poisson’s equation and then treat the limits of its solutions, the central limit theorem is instantly given by the convergence of the moment.

The chemical composition of the leaf extracts of Oroxylum indicum (L.) was found to contain alkaloids, flavonoids, glycosides, tannins and steroids. The total polyphenol and flavonoid contents of Oroxylum indicum (L.) leaves in ethyl acetate extracts (60.56±0.30 mg GAE/g and 235.29±2.88 mg QE/g, respectively) were higher than those in the other three extracts including ethanol, n-hexane and dichloromethane. The previous study was performed to demonstrate the antioxidant activity and enzyme inhibition of ethanol, n-hexane, dichloromethane and ethyl acetate extracts of Oroxylum indicum (L.). The results showed that ethyl acetate extract has antioxidant activity and inhibitory activity of α-amylase, α-glucosidase enzymes higher than other extracts.

The study was conducted to clarify the prevalence and antibiotic resistance of Salmonella in chickens and environment in some households in Vinh Long province. A total of 322 samples (127 fecal samples and 195 environmental samples) were collected from three households in Vinh Long province for isolation and antibiotics resistance testing by disk diffusion method. The results showed that 20 positive samples were Salmonella. The positive Salmonella isolated from feces (9.45%) was higher than that from environmental samples (4.10%). Salmonella was isolated from diarrheic chickens (8/44 samples, 18.18%) higher than from healthy chickens (4/83, 4.82%); mainly in 1-2 weeks of age (17.31%, 9/52 samples). Salmonella isolation in the cage with 10.71% was higher than that in the drinking water samples (1.96%) and feed (1.14%). The results of antibiogtic resistance to 14 antibiotics showed that these strains were resistant to 2 – 10 antibiotics. Salmonella had a high resistance to ampicillin (100%), chloramphenicol (95%), cefuroxime, streptomycin, tetracycline (90%), doxycycline (85%) and moderate resistance to trimethoprim/sulfamethoxazole (60%). These strains are still highly sensitive to amoxicillin/clavulanic acid, amikacin, levofloxacin, ofloxacin (100%), ceftazidime (95%) and colistin (75%). All 20 strains were multi-resistant with 11 different multi-resistant types in very diverse and complicate phenotypes.

A study was carried out in some areas of Dien Bien province to understand the situation of Spirocerca nematode infection in dogs, from 4/2018 to 4/2019, examination by autopsy of 308 dogs showed: 16,56% of dogs infected with S. lupi, of which Dien Bien Dong is the district with the highest rate of infection (21.35%), followed by Dien Bien district (16.98%)  and the lowest is Dien Bien Phu city (12.39%). Between locations there is a different rate of S. lupi infection (P

The objective of this study was to evaluate genetic diversity of 109 soybean [Glycine max (L.) Merr.] samples through agronomical evaluation in spring 2018, protein content and SSR (simple sequence repeats) markers. The results showed that 109 samples were diverse in morphology, growth duration, and yield components. Based on SSR markers, grouped 109 soybean samples were grouped into 5 main clusters with genetic similarity coefficient of 0.66. Protein contents of 22 soybean samples varied from 30.2% - 46.8%, suggesting as materials for protein improvement. Potential soybean samples for yields (HSB0098,  HSB0100, HSB0125, HSB0128, HSB0130,  HSB0132) and for high protein contents (HSB0057, HSB0100, HSB0139, HSB1048) can be used for soybean. Five SSR markers Satt239, Satt270, Satt277 Satt281 and Satt520 provided the most polymorphism.

This study was aimed to isolate and select protease bacteria and determine the most appropriate culture medium to produce proteases. From commercial natto and fresh soybean residue, five bacterial isolates were isolated on casein medium (pH 9.5). N1 isolate with the highest protease activity was chosen to sequence and compared with database GenBank of NCBI by BLAST N software. The results showed that N1 isolate was 99% of the identity with GU980947.1 Bacillus subtilis CICC 10023 and was named Bacillus subtilis N1. The results of the most appropriate medium for the production of protease from Bacillus subtilis N1 was 1% defatted soybean, cultivation pH and incubation time were 8 and 48 hours, respectively, enzyme activity reached 1.870 TU/mL. The crude protease was the alkaline protease with the optimal pH in the range of pH 8-9 and had the fibrinolytic activity.

Lodging resistance and increasing in the number of tillers for rice that farmers has been used Paclobutrazol (PBZ) for a long time. The study was conducted to aims at: (i) investigating farmers' habits of using Paclobutrazole on rice, (2) evaluating PBZ residues in soil and (3) evaluating PBZ absorption ability from soil into rice. The experiment was conducted in randomized complete block design (RCBD) with four treatments (T1: 1,5 kg PBZ / ha, T2: 3,0 kg PBZ/ ha, T3: 1,0 kg PBZ /ha, T4: 0 kg PBZ /ha) and four replications. Based on the investigated results of farmers showed that PBZ have been using for a long time, PBZ was used by farmers in combination with fertilizer application into two stages of 20 to 25 days after seeding (DAS) and 40 to 45 DAS (63,3 %), an average dosage was 1,55kg/ ha. The results showed that T2 and T3 treatments were effective to reduce the height of rice plants, increase the number of shoots per unit area but did not increase rice yield. PBZ treatments had residue in leaf stalks (T1: 60 µg, T2: 2.220 µg, T3: 1.090 µg, T4: 34 µg), rice seeds (T1: 104 µg, T2: 550 µg, T3: 110 µg, T4: 0 µg) and in soil of after harvesting rice (T1: 16,3 µg, T2: 24,0 µg, T3: 9,90 µg, T4: 6,60 µg).

This study was aimed to determine the biological characteristics relating to flowering, and fruit development of Ri-6, a recently favorite and popular durian variety. Observations were implemented on 6 Ri-6 trees at the age of 7-year-old located in Ngu Hiep commune, Cai Lay district, Tien Giang province from Apr. 2017 to Jan. 2018. Results showed that anthesis prolonged within 25 days since that of the first flower detected. Anthesis occurred at 4-5 PM and primarily on the 4-12th day of the process with a peak on the 6th day.  Fruit set ratio was 82%. Fruit development occurred within 97 days since fruit set (DSFS). Young fruit abscission took place mostly from 0-14 DSFS (71.7%). Fruit developed through three stages, viz. stationary (0-14 DSFS), fast growing (42-70 DSFS), and mature-ripening stage (70-97 DSFS). Fruit flesh started to grow from 42 DSFS. Fruit reached to the maximum growing rate on 56 DSFS. At harvesting time, average fruit weight is 2,985.0 ± 503.1 g, with 31.6% of edible portion. The percentage of seedless fruit was 29.5%. Physiological disorders (14.4% of locules and 14.2% of pulp units) were observed at 70-97 DSFS.

The study was aimed at isolating and selecting indigenous fungi capable in decomposing organic materials from 14 different indigenous microorganism communities collected from various different farming ecosystems in Soc Trang province. The Bushnell Haas Medium (BHM) containing 1% carboxymethyl cellulose (CMC) was used to isolate fungi and to qualify for cellulase enzyme activity with Congo Red 0.25% reagent. The activity of cellulase enzyme was determined by 2- hydroxy – 3.5 - dinitrobenzoic acid reagent (DNS) at a wavelength of 540 nm. Decomposition efficacy of selected fungi for organic materials was determined by the mass loss method after 30 days of inoculation under laboratory conditions. The results showed that 56 indigenous fungi were isolated and of which 36 produced a halo zone of 1.67 to 25.7 mm in diameter. The cellulase enzyme activity of 10 selected fungi ranged from 2.52 to 16.5 UI/mL/h. Results from the decomposition experiments for three different organic materials revealed that H3-1, H9-6 and H4-7 were found to be the highest decomposers for rice straw, cattail and water hyacinth with 59.13%, 78.3% and 63.1% dry mass loss, respectively after one month. Especially, isolate labeled as H7-4 decomposed very well for 3 types of materials with a total dry mass loss up to 40.7, 68.7 and 47.9%, respectively after one month. Results from 28S rRNA sequences of four selected fungi indicated that H9-6 had 100% of similarity index with Aspergillus oryzae and 3 other remained fungi (H3-1, H4-7 and H7-4) were highly homologous with Aspergillus niger.

In the nitrogen cycle, nitrite is produced by the biological oxidation of ammonium under aerobic condition. Ammonium accumulated in aquaculture ponds due to feed leftovers and wastes is oxidized to nitrite by bacteria. Increased concentration of nitrite in ponds poses toxic effects to fish, shrimp resulting in low yield and quality. This study aimed at isolation and screen for indigenous bacteria capable of effectively transforming nitrite. Sixteen bacterial isolates were isolated from water and sediment samples collected in shrimp ponds in Bac Lieu. These isolates grew in liquid minimal salt medium supplemented with NaNO2as the only nitrogen source. The data showed that isolates BLS1.3, BLW2.2 and BLW2.4 were able to transform nitrite with higher efficiency than the others (>56.3%) after 7 days of incubation. Among the three isolates, BLW2.2 was the most potential one for the conversion of nitrite, obtaining 97.2% after 3 days of inoculation.

This study investigated seasonal changes of environmental conditions and gonad development of the mud clam, Geloina sp. originated from U Minh Thuong district, Kien Giang province, the Mekong Delta of Vietnam. Specimens were collected with a number of 30 clams per month in 12 months continuously for histological technique to investigate the gonad development of male and female mud clam. The findings showed that gametogenesis of Geloina sp. occurred year around with gonadal index varied from 2.75 (June) to 3.70 (December). The high spawning synchronization was observed in February-March, April-May and in December with >50% collected individuals in spawning stage. The results also showed that egg diameters of mud clams were  from 15 µm to 41 µm with highest value in March (40.8 µm) and December (41.4 µm). Results from this study provide more information on the reproductive biology of mud clam at the studied area, and it could be useful for resource management, bio-conservation and commercial culture of this clam species in the near future.

The objective of this study is to analyze the impact of factors on the competitiveness of seafood exporting enterprises in the Mekong Delta. Data used in the study was collected from 155 enterprises via convenient sampling methods. The results from Cronbach’s Alpha, EFA, and linear regression analyses show that there are four groups of factors affecting the competitiveness of seafood enterprises including source of material, human resources, characteristics and capabilities of enterprises, and ethics and social responsibilities association of businesses. Based on the results, four administrative implications were proposed to improve the competitiveness of seafood exporters in the Mekong Delta.

The paper shows how to generate equivalent multiple-choice math questions automatically. Firstly, a general multiple-choice question, containing a set of parameters, is generated. Then, different values are assigned to these parameters to create equivalent multiple-choice questions. Parameter assignment is performed via the Sagetex, an instruction package of Latex. This package allows embedding Sagemath, a computer algebra software, into Latex, a document preparation system. Creating equivalent multiple-choice questions will help evaluate learners more accurately and fairly.

This study is to assess the quality of life of the ethnic minorities in Can Tho city and Kien Giang province through specific aspects. The research data was collected through documentary study, questionnaire survey, interviews and field trip in the research areas. The research results have clarified some indicators of the life quality including low average income, low literacy rate, health care and medical service with limitations; and unguaranteed living conditions and environment. Thereby, a number of solutions were proposed such as upgrading traffic transportation system thanks to funded capital, selecting suitable livelihoods, consulting and training appropriate works for ethnic minority laborers; improving rural broadcasting system; and reducing tuition fee for ethnic minorities.

The relationship between inflation and economic growth has been a controversial issue so far. Recent studies have found a non-linear relationship between inflation and economic growth, while finding inflation thresholds as the optimal inflation at which economic growth is at its best. In this study, the threshold regression model proposed by Hansen (1999) was used to estimate the inflation threshold in Vietnam at 3,79%. When inflation is less than 3,79%, inflation will accelerate economic growth, whereas inflation is greater than 3,79%, inflation will negatively impact economic growth. The above results showed that the government and the State Bank of Vietnam should have monetary policies to maintain inflation around 3,79% in order to achieve optimal economic growth.

The purpose of this paper is to analyze the impact of corporate social responsibility on brand value and organizational commitment through labors’ perception at the seafood companies in the Mekong Delta. This study data were collected from 430 laborers working in the seafood companies through a well-designed questionnaire with quota sampling method. The research used various testing of Cronbach’s alpha coefficient, exploratory factor analysis, and multivariate linear regression analysis. The results showed that all five factors such as economic responsibilities, ethical responsibilities, legal responsibilities, philanthropic responsibilities and environmental responsibility have impacted positively on organizational commitment of employees. However, the impactive level of these factors is different from that model of Carroll (1991). These results might contribute to support for businesses in implementing corporate social responsibility to promote organizational commitment of labors.

Under the context that the impact of salinity intrusion on coastal households' livelihood activities is increasingly serious, the study on status of using livelihood assets in order to propose strategic solutions for improving livelihoods of coastal farmers is essential. Face-to-face interviews were conducted with 298 households in 10 villages of An Minh (Kien Giang) and My Xuyen (Soc Trang) districts. Multiple regression model was used to analyze the factors affecting the livelihood output. The research results show that human capital is quite abundant, social capital is limited, land area is quite large, financial capital is moderate, and physical capital basically meets production and living needs. Access to credit and experiences were negatively correlated with the livelihood output while farmland area, total investment, total value of production and living facilities had positive relationship with the livelihood output. In order to improve the adaptive capacity and use more efficiently available livelihood assets, physical and financial capital are the two factors that need to be further supported and invested so that farmers can make use other assets (human, social and natural assets) more efficiently.

The study was aimed to explore and analyze the mediating role of brand love for Phu Quoc fish sauce brand - Vietnam. Research data were collected from 418 customers using Phu Quoc fish sauce in Ho Chi Minh City. The scales were assessed by Cronbach's Alpha coefficient, Exploratory Factor Analysis (EFA), Confirmatory Factor Analysis (CFA) and the hypotheses were tested through Structural Equation Model (SEM). The results showed that both hedonic product and brand self-expression are positively affecting brand love and brand love impacted on word of mouth more strongly than brand loyalty.

Destination image is seen as the fundamental premise of destination loyalty and is a prerequisite in choosing a tourist destination of travelers. This study is aimed at measuring the impact of Hue destination image factors on the loyalty of Asian tourists based on the survey of 160 Asian tourists coming to Hue. The results show that among the four factors that make up the destination image of Hue, experience value has the most positive impact on Asian travelers’ loyalty. Tourists are more likely to agree that they will introduce a positive destination ofHue to relatives and friends than going back to the destination in the near future. Based on the results, several measures were proposed to improve tourists’ loyalty, in which the most importance is to emphasize the role of the DMO organization in building and positioning images of Hue destination.