Published: 2020-12-30

Willingness to pay for air quality improvement in Ho Chi Minh City, Vietnam

Han T. N. Le, & Hung D. Bui
Electronic version: 30 Dec 2020 | DOI: 10.52997/jad.5.06.2020
Abstract | PDF (366.5K)

Abstract

This research aimed to estimate people’s willingness to pay (WTP) to improve air quality in Ho Chi Minh City (HCMC), Vietnam. Contingent value method (CVM), the single bounded dichotomous choice question format, was employed. Five levels of bid were used, including 10,000; 20,000; 30,000; 40,000; 50,000 VND. A survey was conducted with 600 people, distributed in 8 districts. The results showed that people had limited perception on specific terms, but they understood the phenomenon and the consequence of air pollution. The mean willingness to pay (MWTP) for air quality improvement was 19,147.06 VND/person per month (0.83 USD/person per month) (with protesters) and 28,157.01 VND/person per month (1.22 USD/person per month) (without protesters). The total budget that would be used for air protection in HCMC was 86,927,652,400 VND/month (3,779,463.15 USD/month) (with protesters) and 127,832,825,400 VND/month (5,557,557.62 USD/month) (without protesters). The income, education level and bid level were the factors affecting their WTP.

Combining ability assessment of agronomic characteristics of 8 inbred sweet corn lines

Phuong Nguyen, Hoa T. Vo, Van T. H. Duong, Thanh T. T. Nguyen, Quoc T. Ho, Nghiem T. Le, & Tuong T. N. Nguyen
Electronic version: 30 Dec 2020 | DOI: 10.52997/jad.1.06.2020
Abstract | PDF (366.1K)

Abstract

This study was conducted to evaluate 28 sweet corn hybrid combinations to determine the combination ability of 8 lines of sweet corn inbred (K60, R111, N1, N4, N5, N7, N8 and N12) of a S8 generation. The results showed that the yield of hybrid combinations was in a range of 14.2 to 23.7 tons/ha. Especially, the hybrid combination THL9 had a yield of 23.7 tons/ha, reached the soluble solids content of 13.9%. Meanwhile, the yield of the hybrid combination THL14 reached 21.4 tons/ha and its soluble solids content reached 13.6%. This result was higher than Golden Cob which was the control variable in this study, and had a yield of 17.4 tons/ha and a soluble solids content of 12.2%. Evaluating the combining ability of the yield and total soluble solids content of 8 lines of sweet corn showed that the N4 lines had a higher combining ability than the other lines in terms of fresh corn yield and total soluble solids content. R111 line and N4 line could combine good productivity (Ŝij: 2,433*) and total soluble solids content (Ŝij reached 0.963*).

The presence and genetic characteristics of porcine circovirus 3 from pigs in Southern and Central provinces of Vietnam

Toan T. Nguyen, Phat X. Dinh, Giao N. P. Trinh, & The N. Nguyen
Electronic version: 30 Dec 2020 | DOI: 10.52997/jad.3.06.2020
Abstract | PDF (506K)

Abstract

Porcine circovirus type 3 (PCV3) is an emerging circovirus species that has recently been reported in different countries around the world, suggesting a widespread circulation. This study was carried out in order to investigate the presence and further genetic characteristics of PCV3 from swine herds in Southern and Central provinces of Vietnam. A duplex PCR assay for rapid detection of PCV3 in pigs was established with a pair of specific primers designed between rep and cap gene segment to amplify full-length ORF2 and another set of primers binding to COX1 gene serving as an internal amplification control (IAC). The resulting duplex PCR was used to examine PCV3 presence in 94 tissue and serum samples. Subsequently, PCV3 was detected in 10 out of 94 cases (10.6%). The infection rate in sows (14.3%) was higher than that in grower pigs (7.7%). Regarding nucleotide sequence comparison, 10 ORF2 genes were selected for nucleotide sequencing and their alignment showed 97.2% - 99.5% homology. According to the phylogenetic analysis and sequence alignment of cap gene, all the sequences were clustered into group PCV3a, including 9 strains of sub-group PCV3a1 and only one strain of sub-group PCV3a2. These findings indicated that the PCV3a group is circulating in swine farms in Vietnam. This study provides better insights into epidemiology of this pathogen in the national swine industry.

Risk factors associated with canine parvovirus disease in dogs: A case-control study

Hien T. Le, Minh H. D. Nguyen, Phu H. Doan, Luyen P. Truong, Linh T. K. Tu, Quynh H. Nguyen, Lien T. B. Nguyen, & Pornpanom Pornchai
Electronic version: 30 Dec 2020 | DOI: 10.52997/jad.4.06.2020
Abstract | PDF (429.5K)

Abstract

Canine parvovirus type-2 (CPV-2) is one of the most contagious viral agents causing acute enteritis in pups with high rate of morbidity and mortality. The study aimed to investigate the risk factors associated with canine parvovirus (CPV) occurrence in dogs in Ho Chi Minh City, Vietnam. A total number of 132 dogs less than six months of age were recruited in the study and split into two groups: 'CPV diseased dogs' included 44 (33.3%) dogs positive with canine parvovirus confirmed by rapid immuno-migration test, and ‘normal dogs’ consisted of 88 (66.7%) healthy dogs. Results indicated that the unvaccinated dogs had 11.76 times more risk of CPV infection than vaccinated dogs (OR = 11.76, P

Seroprevalence of serotype O of foot-and-mouth disease virus in vaccinated pigs and cattle in Ho Chi Minh City

Mai C. Duong, Vy T. Tran, Long N. T. Duong, Phuong P. B. Nguyen, Thanh D. H. Le, & Hien T. Le
Electronic version: 30 Dec 2020 | DOI: 10.52997/jad.2.06.2020
Abstract | PDF (1.3M)

Abstract

The aim of this study was to assess the seroprevalence against serotype O FMD (foot and mouth disease) virus in vaccinated pigs and cattle in Ho Chi Minh City, as a basis to serve the prevention of FMD epidemics in these animals. A total of 535 pigs and 366 cattle sera were tested by using the Elisa kit for the detection of serotype O FMD antibody (Pirbright, UK). Results of this study showed that most pig farms had the proportions of positive animals for antibodies against FMDV serotype O which met the requirements of Decision no. 07/2016/Ministry of Agriculture and Rural Development, except Xuan Thoi Thuong, Thai My and Phu My Hung. All sows had high levels of antibodies against serotype O FMD virus. There were no significant differences in the ratios of positive pigs for antibodies against FMDV serotype O among types of pig and age groups. However, there were significant differences in the seroprevalence of vaccinated pigs across herd sizes and days post-vaccination. Meanwhile, the overall seroprevalence of vaccinated cattle against FMDV at individual-level was over 80.00%. No statistical differences were found in the seroprevalence of vaccinated cattle against type O FMDV among regions, types of cattle, herd sizes, age groups and days post-vaccination. In conclusion, pigs raised in farms of Xuan Thoi Thuong, Thai My and Phu My Hung communes should be revaccinated with FMD vaccine to prevent the risk of pigs being infected with FMD virus and reduce the amount of virus produced by an infected animal.

Effects of drying methods on color retention and chlorophyll of celery (Apium graveolens L.), spinach (Spinacia oleracea L.), Malabar spinach (Basella alba L.)

Thao T. T. Nguyen, Dat T. Huynh, Dat Q. Tran, Hai V. Luong, Ha T. T. Do, & Hanh H. Nguyen
Electronic version: 30 Dec 2020 | DOI: 10.52997/jad.6.06.2020
Abstract | PDF (640.1K)

Abstract

Dried vegetables are considered convenient for storage, transportation and preservation. The different drying techniques could influence the quality of resulting products. This study aimed to evaluate the effects of three distinguish drying methods as hot-air drying, foam-mat drying and microwave drying on the color retention and chlorophyll of green vegetables powder. Fresh spinach (Spinacia oleracea L.), celery (Apium graveolens L.), Malabar spinach (Basella alba L.) were dried by different methods: hot-air at 60oC, foam-mat at 60oC and microwave at 270 W until the samples reached approximately 9% of moisture content (wb). The drying time of the dried samples by microwave, foam-mat and hot-air method were 60, 210 and 240 min, respectively. Foam-mat dried vegetables were found to have the best quality in terms of color and the residual chlorophyll content. The findings suggest that foam-mat drying is promising in dried vegetable processing.

Assessing the status of mechanization and proposing technical solutions for lime farming in the Mekong River Delta

Anh H. Hoang, Tuyen C. Kha, Thanh T. Le, & Dat T. Huynh
Electronic version: 30 Dec 2020 | DOI: 10.52997/jad.7.06.2020
Abstract | PDF (1.3M)

Abstract

This study was conducted to assess the current status of mechanization in lime growing activities of farmer households in the Mekong River Delta. The current status of mechanization was assessed through different groups of criteria that reflect the scale of mechanization level, resources of farmers applying mechanization, results, and production efficiency. The level of machine and technology application was assessed by building the mechanization index. With a sample of 555 lime farmer households in Long An and Ben Tre, the results showed that the application of machines and equipment in lime growing activities in the study area was quite limited. Households mainly used machines in two stages including land preparation (42% of households applying mechanization) and tree care (93%). The growth rate and mechanization investment of the 2016-2019 period were almost unchanged. The estimated results of mechanization index showed that most of lime growers had a very low mechanization application level with an average value of only 0.09. In fact, 2% of the surveyed households do not invest in mechanization in lime production, 89.8% are in the group with very low mechanization level, 3.1% at low mechanization level, only 5.1% at medium mechanization level and no household had high mechanization application level. From the survey results, potential technical solutions for lime farming in the Mekong River Delta were also proposed, including mechanization for small and medium farms and mechanization considerations for plant care. Finally, in order to improve the quality of lime fruit, the semi-mechanization harvesting systems and appropriate storage facility and suitable packaging are highly recommended.

Effect of glycerol concentration on physical and texture properties of edible films prepared from karaya gum

Tung T. Diep, Viet B. Nguyen, Vi N. H. Vu, & Nhan P. T. Nguyen
Electronic version: 30 Dec 2020 | DOI: 10.52997/jad.8.06.2020
Abstract | PDF (376.6K)

Abstract

This study formulated edible films based on karaya gum in the presence of glycerol. Physical properties of films were investigated by various methods including texture analysis and differential scanning calorimeter (DSC). The obtained results revealed that glycerol acted as a plasticizer contributing to improve the flexibility, water vapor permeability and heat resistance of karaya films. The best value of tensile strength and puncture force for edible films could be achieved by the combination of karaya gum and glycerol at the concentrations of 4% (w/v) and 10% (w/w), respectively.