Search

Search Results

##search.searchResults.foundPlural##

Study on the Application of Fly Ash for Soil Amelioration

Nguyen Ngoc Tu, Trinh Quang Huy, Vo Huu Cong, Nguyen Thi Thu Ha, Dinh Thi Ha, Ho Thi Thuy Hang

Received: Sep 16, 2021 / Published: Sep 30, 2022
In this study, pot culture experiments were carried out to investigate the most suitable level of fly ash for the amelioration of soil that can enhance the management of fly ash. The fly ash recovered from the Mong Duong 2 coal-fired thermal power plant and had the main chemical composition of oxygen (43%), Si (26%), Al (15%), K (9%), and Fe (6%). The addition of fly ash to light texture soil increased some of the basic properties of the soil, such as moisture, cation exchange capacity, mechanical composition, and organic matter content. The results of the performance evaluation of an experimental crop (soybeans) showed the effects of the amended soil on the growth of the experimental plants, namely the number of fruits, number of nodules, and their dry biomass. The incorporation of manure into the sandy soil was amended with fly ash in the pot experiment as a single application of fly ash may not provide enough nutrients for plant growth despite its ameliorant effect on soil structure. The appropriate fly ash addition rate from 10-30% w/w is recommended in soil amelioration applications based on the results of this study. This research opens up an application direction for fly ash, a by-product generated from the operation of coal-fired power plants in Vietnam.
Phytochemical Analysis and Antioxidant and Alpha-glucosidase Inhibitory Activities of the Stem Bark of Dialium cochinchinense Pierre

Tran Thi Thu Trang, Lai Thi Ngoc Ha, Doan Thi Thuy Ai, Nguyen Thi Hien, Nguyen Thi Thu Tram, Vu Thi Huyen

Received: Jun 18, 2020 / Published: Mar 30, 2022
The purpose of this study was to determine the phytochemical compositions and to evaluate the biological activity of the stem bark of Dialium cochinchinense. The phytochemical analysis showed the presence of steroids, terpenoids, anthraquinones, saponins, and phenolics in the stem bark of D. cochinchinense. The optimal extraction conditions were 70% ethanol at 30°C for 40min with a material/solvent ratio of 1/20. Under the optimal conditions, the corresponding predicted response value for the total phenolic content was 100.80 ± 0.40 mg GAE/g DW. The evaluation of antioxidant activity indicated that the polyphenol-rich extract was a good source of antioxidants as measured by the DPPH assay with the IC50 of 3.81 ± 0.58 μg mL-1. The extract also demonstrated a strong a-glucosidase inhibitory activity with the IC50 value of 2.14 ± 0.05 μg/mL. Therefore, D. cochinchinense could be useful as a potential preventive intervention for free radicals in mediated diseases as well as an antioxidant drug and a potential source in treating diabetes mellitus in the pharmaceutical industry.
Detection of Swine Dysentery (SD) caused by Brachyspira hyodysenteriae via PCR in Northern Vietnam

Nguyen Thi Thu Hang, Truong Quang Lam, Dao Le Anh, Nguyen Thi Hoa, Nguyen Thi Lan, Nguyen Thi Thuy Dung

Received: Oct 22, 2020 / Published: Oct 29, 2021
This study aimed to diagnose swine dysentery (SD) caused by Brachyspira hyodysenteriae in pigs by the PCR method in Vietnam. Of the 250 samples, 29 isolates of B. hyodysenteriae (11.60%) were identified by PCR in seven provinces of Northern Vietnam, and the infection rate differed from region to region. From the positive cases of B. hyodysenteriae, we analyzed B. hyodysenteriae infected cases according to the ages of the pigs, farm sizes, and veterinary hygiene practices to get more information about the disease in Vietnam. The results showed that the positive B. hyodysenteriae samples were commonly seen in post-weaning pigs (32.14%) in households (20.73%) with poor hygiene (24.69%). Clinical signs of SD included high fever (100%); anorexia (100%); watery, bloody diarrhea, usually gray to brown in color (100%); and weight loss (86.42%). Gross lesions of SD were limited to the large intestine were described as having a fibrinous, blood-flecked membrane covering the mucosa (93.75%), swollen with hemorrhaged colon and cecum (75.00%), and mesenteric lymph nodes (81.25%).
Effects of Culture Conditions on the Antibacterial Activity of Streptomyces Spp. against Erwinia Spp. Causing Soft Rot Disease on Asparagus Officinalis

Nguyen Thanh Trung, Nguyen Thi Van Anh, Tran Thi Dao, Nguyen Thanh Huyen, Pham Le Anh Minh, Pham Hong Hien, Nguyen Xuan Canh

Received: Aug 31, 2020 / Published: Aug 10, 2021
Erwinia is a genus of Enterobacteriacea containing mostly pathogens, which cause soft rot disease in many ornamental plants and crops, including Asparagus officinalis. Chemical treatments to control Erwinia have lost their attractiveness because of the development of resistant strains and the negative impacts on the environment and human health. Therefore, the study of biological controls of soft rot disease has gained great importance. There are several types of microorganisms that show activity against Erwinia spp. such as Pseudomonas fluorescence, Bacillus subtilis, and Streptomyces spp. Among them, Streptomyces spp. are found to be the most effective control agents. In this study, 64 isolates of Streptomyces were screened for their antibacterial activity against Erwinia spp. The results indicated that 18 isolates showed an antagonistic reaction against Erwinia spp. Among them, isolate D5.1 showed the highest inhibition activity. In addition, the morphological and antibacterial activities of isolate D5.1 grown in different conditions were also characterized.
Investigating the Potential of Vietnamese Tea Seed Oil (Camellia sinensis O.Kuntze) for the Enhancement of Oxidative Stability in Vegetable Oils

Phan Thi Phuong Thao, Tran Thi Thu Hang, Pham Le Nguyet Anh, Vu Hong Son

Received: Mar 06, 2020 / Published: Jun 18, 2021
This study examined the effectiveness of different antioxidative compounds, namely 0.2% BHA (Butylated hydroxyanisole) + BHT (butylated hydroxytoluene), 0.03% α – tocopherol, and 3% and 6% tea seed oil (TSO) on the oxidative stability of vegetable oils. Four commonly used oils, viz. rapeseed oil (RSO), peanut oil (PNO), sunflower oil (SFO), and soybean oil (SBO), were assessed by the Schall Oven test method and monitored during the 12-day preservation period under 60°C. The total oxidation values (TOTOX) of the samples treated with 6% TSO were lower than those treated with 0.2% BHA+BHT. The results indicated the potential of TSO as a novel natural antioxidant for dietary vegetable oils. Our study also suggested that TSO could serve as an effective substitution for currently used synthetic antioxidants such as BHA and BHT.
A Study on the Tax Obligations and Perceived Tax Compliance of Small and Medium Enterprises (SMES) in Gia Lam, Hanoi

Nguyen Thi Huong, Dao Thi Hoang Anh, Dang Thi Hai Yen, Bui Thi Hong Nhung, Le Thi Thanh Hao

Received: Jun 12, 2020 / Published: Mar 05, 2021
This study was conducted to examine general information of tax obligations and perceived tax compliance for small and medium enterprises in the district of Gia Lam district. To achieve these objectives, 150 small and medium enterprises were randomly selected and analyzed using descriptive analysis and Principal Component Analysis (PCA). The results show that most of enterprises got difficulties in register, declare and pay taxes, and nearly half of them had submitted taxes lately. Besides, perceived tax compliance of enterprises could be divided into five key factors, including: "Quality of tax services"; "society norms"; "Technology Application"; "Enterprise responsibility "; and "Quality of tax officials". Based on these results, some recommendations could give to the tax authorities in order to improve tax regulations and policies.
Successful Application of Site-directed Mutagenesis Polymerase Chain Reaction to Mutate TMS 11 of the Staphylococcal Multidrug Efflux Protein QacA

Nguyen Thi Hang, Vu Duc Hanh, Dam Van Phai, Lai Thi Lan Huong, Nguyen Thi Phuong, Le Van Truong, Chitsaz Mohsen, Melissa H Brown

Received: Mar 14, 2019 / Published: Aug 12, 2020
Staphylococcus aureus is a major problem in both the clinical setting and within the community. S. aureus can quickly develop resistance to a wide range of antibiotics through a number of different mechanisms, of which, using transporters located in the cell membrane to pump antibiotics out of the cell is the most serious concern. In staphylococcal species, QacA, one such important transporter, is encoded by qacA. QacA is 55kD in size and has 14 transmembrane segments (TMS) (TMS 1-TMS 14). This research describes the mutation process of the amino acid residues in TMS 11 of QacA using site-direct PCR. In this research, 15 primers were successfully designed for site-directed mutagenesis PCR. The site-mutagenesis PCR was successfully conducted to create 15 qacA mutants. These mutants will be used in further functional research of QacA.
Comparison of Genetic Gains of Agronomical Traits from Different Selection Methods in Soybean

Vu Thi Thuy Hang, Vu Dinh Hoa, Le Thi Tuyet Cham, Nguyen Thanh Tuan, Pham Thi Ngoc, Nguyen Phuong Thao

Received: Feb 18, 2019 / Published: Mar 12, 2019
This study aimed to compare the genetic gains of two different selection methods for agronomic traits in soybean. A population from the cross of VI045032 x 4904 (LSB10) was advanced using the bulk method and modified bulk method to the F6 generation. Measured traits were growth duration, plant height, height of the first pod node, number of pods per plant, the percentage of 3-seeded pods, 100-seed weight, individual yield, and yield. Both methods were equally efficient and could be used for segregating and the stabilizing phase of progenies/populations of soybean crosses. However, the bulk method appeared to be more efficient for the improvement of yield-related traits while the modified bulk method was more efficient for the improvement of morphological traits.
The Influence of Bulb Storage Regimes on the Growth and Flowering of Hippeastrum (Hippeastrum hybridum Hort.)

Huyen Trang Thi Pham, Nam Van Dinh, Thanh Nga Thi Trinh, Thu Ha Thi Phung, Thuy Hanh Thi Nguyen, Hoa Hanh Nguyen

Received: Oct 19, 2018 / Accepted: Oct 22, 2018 / Published: Oct 22, 2018
Hippeastrum hybridum cultivar ‘Cam Tu’ bulbs were subjected to ten different treatment regimens to evaluate the effect of temperature (4°C or 25°C), duration (4, 6, or 8 weeks), and wrapping materials (coir fiber or newspaper) on their growth and flowering. The data revealed that the storage treatments had significant effects on several growth and flowering characteristics of H. hybridum cv. ‘Cam Tu’. In terms of vegetative characteristics, bulbs stored at 4°C with coir fiber wrapping for 6 weeks (T9) had the largest leaf size (a length of 39.46 cm, a width of 4.39 cm), the longest flower scape (48.64 cm in length), and the longest pedicel (4.75 cm in length). Bulbs of the T9 treatment also showed the shortest time to flower bud emergence (62.24 days) and first flower opening (80.43 days), and the date of 70% first flower fully opening was January 19, 2018. Both of the two thermal treatment regimens shortened flowering time (80.43-103.16 days) compared to the control (132.46 days). However, the number of bulblets per plant, number of leaves per plant, number of florets per scape, floret diameter, longevity of a flower, and longevity of a flower scape were not statistically impacted by the treatments.
Polymorphism Candidate Genes of Lien Minh Chickens

Binh Nguyen Thi Tran, Duc Huu Nguyen, Quy Duc Vu, Giang Thu Pham, Linh Manh Nguyen, Ngoc Thuy Thi Dinh, Dieu Thuy Thi Nguyen

Received: Oct 17, 2018 / Accepted: Oct 22, 2018 / Published: Oct 22, 2018
Lien Minh chicken is an indigenous breed with several favorable properties, such as high productivity and good meat quality, and is associated with the economic development of the people in the Lien Minh village, Cat Hai, Hai Phong. The objective of the current research was to investigate the single nucleotide polymorphisms (SNPs) of candidate genes, which might be associated with broodiness and egg production traits. Ninety Lien Minh chicken individuals were genotyped for five SNPs of chicken prolactin (PRL), Vasoactive Intestinal Peptide (VIP), neuropeptide Y gene (NPY), growth hormone (GH), and growth hormone receptor (GHR) genes. Blood samples were used for DNA extraction and then for genotyping by the PCR-RFLP method. The allele frequencies obtained were as follows: 0.19 and 0.81 for alleles C and T (PRL-C2161G), respectively; in VIP (G5138982T), 0.55 for the G allele and 0.45 for T; in GH-SacI (the intron 4), 0.02 for A and 0.98 for B; and in GHR-NspI, 0.82 for C and 0.18 for T. The NPY gene (four nucleotide indel) had the frequencies of 0.86 for I and 0.14 for D. The four studied polymorphic loci (PRL, VIP, NPY, and GH) were in Hardy-Weinberg equilibrium in the Lien Minh chicken population. These are the initial results, which can be used to analyze the correlation of molecular markers and egg production traits in Lien Minh chickens.
Effects of Osmotic Stress Induced by Peg and NaCl on the Germination and Early Growth of Mung Bean

Thang Ngoc Vu, Khuynh The Bui, Gioi Huy Dong, Tuan Anh Tran, Tuyet Cham Thi Le, Chinh Dinh Vu

Received: Oct 15, 2018 / Accepted: Oct 19, 2018 / Published: Oct 22, 2018
This study was performed to evaluate the effects of osmotic stress (measured by different water potentials) induced by Polyethylene Glycol 6000 (PEG) and NaCl solutions at the germination stage of five mung bean varieties (DX11, DX208, DX14, DX17, and DX22). Five water potentials: 0 (control), -0.15, -0.49, -1.03, and -1.76 Mpa were used as treatments in this study. The germination rates, root and shoot lengths, root and shoot fresh weights, and dry weights of the plants were measured. The results showed that the germination rate of the mung bean varieties decreased with increased NaCl or PEG concentrations. The germination rates of the mung bean varieties in the PEG treatments were higher than those in the NaCl treatments. In addition, low water potentials induced by NaCl (-1.76 Mpa and -1.03 Mpa) inhibited germination and seeding growth of all the mung bean varieties. The growth parameters of the mung bean seedlings, such as root and shoot lengths, fresh weights of roots and shoots, and plant dry weights, were reduced under low water potentials treated with either PEG or NaCl. However, more severe damage in seedling growth was observed in the NaCl induced treatments. Amongst five mung bean varieties used in this study, DX17 was more drought and salt tolerant than the other mung bean varieties.
The Effect of Credit Risk on the Financial Performance of Commercial Banks in Vietnam

Dang Thi Hai Yen, Pham Le Thao Trang, Nguyen Thi Huong, Dao Thi Hoang Anh

Received: Dec 15, 2023 / Published: Jun 28, 2024
Creating credit is the main income-generating activity for banks. However, granting credit always comes with risks. Credit risk is the risk of losing part or all of a debt due to failure to pay on time or default. Credit risk is considered the most important risk affecting banking performance. Therefore, this study measured the effect of credit risk on the financial performance of Vietnamese commercial banks. The research sample was made up of 30 commercial banks in Vietnam during the period from 2017 to 2022. There were a total of 180 observations in the balanced data panel. To control for unobserved individual effects, this study used a fixed effects model (FEM) with adjusted standard errors. Return on equity (ROE), return on asset (ROA), and net interest margin (NIM) were the indicators for bank financial performance. The non-performing loan (NPL) rate variable represented credit risk. The control variables were cost to income ratio (CIR), equity to asset (ETA), total loans to total assets (LTA), GDP growth (GDP), and Covid. The research results showed that credit risk had a negative and statistically significant effect on the banks' financial performance. This can be explained by the increase in the NPL ratio, causing banks to increase provisions for loan losses, thereby reducing profits. Reduced profits were also because of poor risk management, information asymmetry, and moral hazards. The study also provided a number of solutions and recommendations to improve bank financial performance.
Current Situation and Solutions for Vocational Training in Extremely Isolated Communes, Lowland and Coastal Areas, and on Islands in Vietnam

Nguyen Dang Hoc, Le Thi Minh Chau, Hoang Thi Mai Anh, Phi Thi Diem Hong, Tran Quang Trung

Received: Oct 10, 2023 / Published: Mar 30, 2024
This study aimed to analyze the current situation of vocational training for farmers and farmers’ needs for vocational training in the next years in extremely isolated communities. The primary data were collected from 480 farmers in 16 communes. The selection of the study sites was based on the list issued in Decision No. 353/QD-TTg dated March 15, 2022 of the Prime Minister. The secondary data on vocational training in the period of 2016-2022 were collected from the Department of Labor, Invalids, and Social Affairs in the study sites. The research results showed that vocational training programs for farmers in the period of 2016-2022 had some achievements. The numbers of courses and trained workers increased every year (except the period of 2020 to early 2022 because of Covid-19), and the contents of the training courses were designed in accordance with the special requirements of local conditions and production and business characteristics. However, the vocational training program for farmers in extremely isolated communes in the period 2016-2022 still had limitations in terms of training contents, training methods, and training duration. It was found that in the 2023-2025 period, 73.5% of surveyed farmers desired to participate in vocational training. Based on the limitations of the vocational training program in the past, some proper solutions were proposed to improve the effectiveness of vocational training and to meet the farmers’ expectations.
Responses to Water Deficit of Mung Bean Cultivars at the Vegetative and Flowering Stages under Greenhouse Conditions

Vu Thi Thuy Hang, Le Thi Tuyet Cham, Phan Thi Thu Hien, Pham Thi Ly

Received: Aug 22, 2023 / Published: Dec 29, 2023
Mung bean (Vigna radiata L. Wilczek) is grown mainly under rainfed conditions, facing water deficits in different growth stages. This study was conducted to evaluate the responses of a local cultivar, Dau tam Thanh Hoa, and three introduced mung bean cultivars (DX14, Mongo Labo, and TV06425) to water stress at the different growth stages. The experiment was carried out in a greenhouse following a completely randomized arrangement with two replications. Drought was induced by withholding water at either the vegetative or flowering growth stages for 20 consecutive days. The control consisted of well-watered plants. After 8, 12, 15, and 20 days of drought, plant available water, growth characteristics, and the weights of fresh stems and roots were measured. After 20 days of drought, plants were watered to assess their recovery after 7 days and the growth characteristics, weights of fresh stems and roots, and yield components at the harvest stage were evaluated. The results showed that drought affected the growth, resilience, and yield-related factors more severely at the vegetative stage than at the flowering stage. The longer drought was imposed, the greater decline in plant growth was observed. Despite the recovery, fresh root mass and root length were still 40-50% and 10-30% worse than the control, respectively. Based on the growth responses and individual yields, Dau tam Thanh Hoa and DX14 were more tolerant to water deficit and can be used as materials for improving the drought tolerance of mung bean.
Traditional and Modern Distribution Channels for Vegetables in Vietnam: A Case Study in Hanoi City

Nguyen Thi Kim Oanh, Doan Thi Ngoc Thuy, Nguyen Thi Thu Trang

Received: Dec 08, 2021 / Published: Sep 29, 2023
This study aimed to provide a clear overview of the vegetable distribution system in Hanoi city which is dominated by traditional combined with the emergence of modern distribution channels, including supermarkets. The analysis was based on secondary data sources, a primary survey among 60 vegetable farmers, and in-depth interviews with other marketing system stakeholders including two agribusiness farms, four agricultural cooperatives, trade intermediaries (five collectors, three wholesalers, and three trading companies), and three supermarkets. Comparative and descriptive statistics were applied to get the full picture of vegetable distribution system, including traditional and modern channels. While traditional distribution channels involved various intermediaries, supermarket channels tended to be shorter due to direct producer-buyer relationships. In addition, while supermarket distribution channels focused on safe vegetables, including VietGAP and organic certified vegetables, there was no difference between safe and conventional vegetables in traditional channels. Therefore, producers may get 50% higher prices when supplying supermarkets compared to traditional channels. Recommended solutions to strengthen the distribution system of vegetables are to encourage the development of agricultural cooperatives, raise vertical integration, and develop sustainable cooperation among stakeholders in the supply chain.
Impacts of Dietary Supplementation of Peptidoglycan Extracted from Lactobacillus sp. on the Growth Performance and Resistance to Streptococcus Agalactiae of Nile Tilapia

Nguyen Thi Mai, Mai Van Tung, Do Hoanh Quan, Vu Thi Thanh Huong, Nguyen Thu Hang

Received: Mar 14, 2023 / Published: Jun 30, 2023
The current experiment aimed to determine the effects of peptidoglycan, known as a prebiotic compound, on the growth, feed efficiency, and disease resistance in Nile tilapia. Fish at an initial body weight of 22.6 ± 0.3g were distributed into a 100 L-glass tank system. Peptidoglycans extracted from Lactobacillus sp. were added to commercial feed at ratios of 0, 5, and 10 g kg-1 diet corresponding to the PG0, PG5, and PG10 treatments, respectively. Fish were then fed at 4% their body weight for four weeks. After a 4-week trial, fish were infected with Streptococcus agalactiae at 50% the lethal dose (1.1×106 CFU mL-1), and monitored for 14 days. After 2 and 4 weeks of the feeding trial (T2 and T4) and on the second day of the bacterial challenge, fish blood samples were collected for hematological analysis. The results indicated that the dietary supplementation of peptidoglycan induced a positive effect on fish growth performance and the highest value was observed in the PG5 treatment. The lowest value of cumulative mortality was also observed in the PG5-fed fish indicating that the dietary supplementation at 5 g kg-1 diet supported the highest resistance to S. agalactiae. In conclusion, the beneficial effects of dietary supplementation of peptidoglycan extracted from Lactobacillus sp. were recorded on the growth performance and disease resistance in Nile tilapia.
Fairness and Transparency in Payment for Forest Ecosystem Services Programs in Vietnam: A Community Based Evaluation

Cao Truong Son, Nguyen Thi Huong Giang, Nguyen Hai Nui, Nguyen Thanh Lam, Tran Duc Vien

Received: Mar 12, 2021 / Published: Jun 27, 2022
Payment for forest environmental services (PFES) has been widely implemented in Vietnam for enhancing the reforestation and conservation of natural resources. However, fairness and transparency in the implementation of PFES programs have not been given due attention. In order to gather the community's opinions about the fairness and transparency of PFES's implementation, two case studies of direct and indirect payment programs in Bac Kan Province were selected to investigate. In this study, a five-point scale to rank the levels of "importance" and "implementation" of eight criteria of fairness and five criteria of transparency were used. There were 167 people who participated in the evaluation process through a questionnaire. The results pointed out that the community highly evaluated fairness and transparency in terms of "importance". Nevertheless, the "implementation" of these criteria had lower evaluation points. In comparing the evaluation results between the service providers and buyers, there were no statistically significant differences in terms of the "important" criteria. However, the difference between providers’ and buyers' evaluations regarding "implementation" were significant, with the mean values of the providers' being relatively higher than the buyers'. In addition, the analyses also found that participants in the direct program evaluated fairness and transparency higher than those in the indirect program. Finally, we state that policymakers and other stakeholders should include fairness and transparency criteria in designing the evaluation framework of PFES programs in Vietnam in order to promote more participation of people and improve the sustainability of PFES programs.
Factors Influencing Imported Beef Purchase Intention: A Case Study in Long Bien District, Hanoi, Vietnam

Nguyen Ngoc Mai, Do Quang Giam, Do Van Vien

Received: Aug 03, 2021 / Published: Mar 30, 2022
The objective of the paper was to analyze the factors influencing the purchase intention of consumers for imported beef in Long Bien district, Hanoi. Quantitative and qualitative methods were employed in this study based on an online survey using a structured questionnaire. The data were collected from 388 consumers who bought imported beef or had an intent to buy in the future. Structural equation modeling (SEM) was used to analyze the data. The results of this study showed that the factor of perceived quality and the factor of clear information on the packaging with the country of origin were the significant factors that increased purchase intention. These factors also contributed to increasing the positive attitudes towards the consumption of imported beef. Attitudes were also a mediating factor that positively influenced purchase intention. In addition, the availability of the product in the market contributed to the stronger purchase intention towards imported beef.
Protection of Geographical Indications in Vietnam: towards Raising the Participation of Producers

Nguyen Thi Minh Hanh, Trinh Thi Ngoc Anh, Le Thi Yen, Vu Van Tuan, Nguyen Thanh Hai

Received: Oct 21, 2020 / Published: Aug 11, 2021
This paper aims to review the current situation of the Vietnamese geographical indication (GI) system from both the legal and practical perspectives. It examines how the top-down approach influences the effectiveness and sustainability of the whole system. Further, the paper refers to the European Union (EU)’s experiences, particularly those of France - a representative of the bottom-up approach - to examine whether a shift to the producer-driven approach in GIs is workable in Vietnam. The paper argues that more active roles should be vested on producers represented by their associations during the course of establishment and management of GIs. Taking into account the capacity of producers and their associations in this current stage, the paper suggests a transition period before the producers assume the leading role in the whole system. During that period, it is recommended to endorse the producers’ role through legal recognition of the producers’ representative organizations, capacity building, and awareness-raising for producers and their associations to achieve desirable outcomes for GI development.
Effects of Nitrogen Application on the Growth and Yield of Quinoa under Saline Conditions in Northern Vietnam

Dinh Thai Hoang, Dang Thi Phuong Anh, Luu Hue Nhan, Nguyen Viet Long

Received: Sep 06, 2020 / Published: Jun 18, 2021
This study aimed to determine the optimum nitrogen application rate for quinoa in saline soils. Two experiments were conducted: (i) the first experiment was under artificial saline conditions with the two factors of saline regime (stressed and non-stressed) and nitrogen application level (0, 30, 60, 90 and 150 kg N ha-1) in net-houses located in Gia Lam, Hanoi; and (ii) the second experiment was under natural field saline conditions with the two factors of quinoa cultivar (Atlas and Moradas) and nitrogen application level (0, 30, 60, 90, and 150 kg N ha-1) in the coastal areas of Hai Hau, Nam Dinh province. Data were collected for growth duration, insect and disease infestations during the growth period, and various growth parameters and yield components at harvest. The results showed that saline stress reduced the growth and yield parameters, but did not affect the quinoa growth duration of the investigated quinoa cultivars. In both experiments, the growth parameters and yield components increased according to the increase of the nitrogen application rates from 0 to 90 kg N ha-1, then decreased when the nitrogen rates were higher. The results suggested that 90 kg N ha-1 was the optimum nitrogen application dose for quinoa growth and development under saline soil conditions.
An investigation on the effect of cutting parameters in CNC plasma cutting process for carbon steel

Pham Thi Hang, Nguyen Thi Chau, An Duong Khang, Nguyen Hoang Anh, Pham Hong Son

Received: Jun 18, 2020 / Published: Dec 31, 2020
The effect of technological parameters such as gas pressure, cutting current, standoff distance, and cutting speed on the cutting surface quality of CNC plasma cutting process was investigated. The experiment was carried out by Bruco CNC plasma cutting machine for CT3 steel with different thicknesses. The quality characteristics examined included the ability to cut out samples, the slag formation on the surface, the surface roughness, and the cut angle. The analysis of the results was made using the Taguchi method in order to determine the contribution of each-individual parameter to the cutting quality, especially surface roughness. The obtained results show that the value of cutting current should be set up at a real value in order to cut out of the sample. The air pressure strongly affected the slag formation. The surface roughness was mainly affected by the standoff distance and air pressure, whereas the cutting speed and cutting current were the minor influencing parameters.
Cassava Farmers’ Perception on Climate Change: A Case Study in Van Yen District, Yen Bai Province

Nguyen Hai Nui, Vu Thanh Bien, Nguyen Duc Trung, Trieu Hong Lua, Nguyen Tuan Cuong, Spillane Charles, Brychkova Galina, McKeown Peter, Bui Le Vinh

Received: Jun 11, 2020 / Published: Mar 05, 2021
Situated in the Northern Mountain Region, one of the most climate-vulnerable regions of Vietnam, Yen Bai province is exposed to many climate risks. This study investigated how well Yen Bai farmers were aware of the impacts of the changing climate on production and their livelihoods and how they referred support programs from the central and local governments to make decisions on adaptation and resilience strategies. Data were collected through direct interviews of 488 cassava households in six communes of Van Yen district. Descriptive statistics, One-way ANOVA, and Chi-square test were used to statistically analyze the data. In addition, we employed the Partial Least Square Structural Equation Modelling (PLS-SEM) to study the relationships of three identified independent variables: (i) understanding of support programs/policies; (ii) access to weather information; and (iii) experience of climate risks and impacts, and farmers’ perceptions of climate impacts. Results from the PLS-SEM model showed that farmers with higher positive scores in the three independent variables above had better perceptions of climate change and its possible impacts, from which better adaptation decisions and strategies could be derived. These research findings emphasized the need for improving the understanding of climate change that could impact farmers’ livelihoods, farmers’ access to accurate near-time and medium-term weather forecasts, and thoroughly using local knowledge on climate risks and effective native adaptation measures for better adaptation and mitigation strategies and actions in rural climate-vulnerable communities in Vietnam.
Chemical Compositions and Food Preservation Ability of White Turmeric Rhizomes Essential Oil

Ngo Thi Thuong, Truong Minh Luong, Luu Thi Hue, Vu Thi Thuy Linh, Nguyen Thi Bich Thuy, Le Thi Thu Huong

Received: Apr 14, 2020 / Published: Nov 30, 2020
White turmeric (Curcuma aromatica Salisb.) has been widely used as a traditional herbal drug both in Vietnam and other Asian countries. In this study, the essential oil of white turmeric rhizomes (collected from Dien Bien province) was extracted and evaluated for its chemical composition and antibacterial potential against E. coli and S. aureus. The raw material was 82.48% in moisture and was steam distilled within 3 days from collection at a 0.4 kg L-1 ratio of raw material/equipment volume for 180 minutes. Under these conditions, the essential oil accounted for about 0.3% of the raw material. The GC-MS analysis showed that the composition of the essential oil consisted of more than 46 substances including a-zingiberene, 17.85%; β-sesquiphellandrene, 13.28%; and ar-curcumene, 9.45%. The white turmeric essential oil exhibited antibacterial activity against gram-positive strains of S. aureus with an inhibition zone diameter of 8.0mm but did not inhibit gram-negative strains of E. coli. Importantly, white turmeric essential oil at a concentration of 0.25% could extend the shelf life of mangoes by at least 5 days more than the control samples.
A Simulation of the Heston Model with Stochastic Volatility Using the Finite Difference Method

Vu Thi Thu Giang, Nguyen Huu Hai, Nguyen Thuy Hang, Nguyen Van Hanh, Nguyen Thi Huyen

Received: Feb 25, 2020 / Published: Sep 29, 2020
In this study, we investigated one of the most popular stochastic volatility pricing models, the Heston model, for European options. This paper deals with the implementation of a finite difference scheme to solve a two-dimensional partial differential equation form of the Heston model. We explain in detail the explicit scheme for the Heston model, especially on the boundaries. Some simple ideas to modify the treatment on the boundaries, which leads to a lower computational cost, are also stated. The paper also covers comparisons between the explicit solution and the semi-analytical solution.
Impact of Farming Models on the Reproductive Performance and Egg Quality of Vietnamese Local Chicken Breeds: Ho and Dong Tao

Nguyen Van Duy, Hoang Ngoc Mai, Nguyen Dinh Tien, Nguyen Thi Phuong, Vu Dinh Ton

Received: Jan 02, 2020 / Published: Jul 22, 2020
The study was conducted from October 2016 to December 2017 at the Experimental Farm, Faculty of Animal Science, Vietnam National University of Agriculture, with the aim to evaluate the interaction between farming model types and reproductive performance of Ho and Dong Tao chickens. The two farming model types used in this research were (1) the traditional type – backyard and (2) the ameliorate type – battery cage. Data were collected from 61 Ho hens and 61 Dong Tao hens continuously during 52 laying weeks. The total number of eggs laid by hens raised in battery cages averaged 88.47 eggs (for Ho hens) and 94.91 eggs (for Dong Tao hens), 35-38% higher than the number of eggs laid by hens raised in a traditional model. The FCR index per 10 eggs laid in battery cages was significantly lower than that in the back-yard model (P< 0.001). In both the Ho and Dong Tao breeds, the rate between the number of embryonated eggs by number of incubated eggs recorded in the ameliorate model was higher than that recorded in the traditional model (P< 0.01 for Ho chickens, P< 0.001 for Dong Tao). The weight of eggs produced by hens raised in battery cages was higher than eggs laid by free-range hens for both Ho and Dong Tao chickens (P< 0.01). As such, the reproductive performances and egg quality of both Ho and Dong Tao breeds were apparently improved when chickens were raised in battery cages.

26 - 50 of 170 items << < 1 2 3 4 5 6 7 > >>

Search

Advanced filters

Search Results