ASSESSMENT OF THE HEALTH AND ECOLOGICAL RISKS CAUSED BY FUNGICIDES IN CHRYSANTHEMUM CULTIVATION BY ENVIRONMENTAL IMPACT QUOTIENT

This study uses the Environmental Impact Quotient (EIQ) to assess the health and ecological risks caused by fungicides used in chrysanthemum cultivation upstream of Xuan Huong Lake, Da Lat city. Survey results reveal that 134 farmers use 21 fungicides with 18 active ingredients on a total area of 35.2 hectares. In all, 18 fungicides with an EIQ at the level of “unlikely to be hazardous” (EIQ < 25) are used on about 95% of the acreage, and 3 fungicides with an EIQ of “slightly hazardous” (25 < EIQ < 50) are used on the rest of the area. The Field Use EIQ of fungicide was rated very low in only 8.2% of the survey area and moderate in 48%. Areas with high and very high ratings account for 3% and 41%, respectively. Using fungicides according to the instructions can reduce the Field Use EIQ values in cultivated areas by 38% and return areas with high and moderate ratings to a low rating. Therefore, it is necessary to instruct farmers on the safe use of fungicides and to recommend those with low EIQ values for chrysanthemum cultivation

ASSESSMENT OF THE HEALTH AND ECOLOGICAL RISKS CAUSED BY FUNGICIDES IN CHRYSANTHEMUM CULTIVATION BY ENVIRONMENTAL IMPACT QUOTIENT

This study uses the Environmental Impact Quotient (EIQ) to assess the health and ecological risks caused by fungicides used in chrysanthemum cultivation upstream of Xuan Huong Lake, Da Lat city. Survey results reveal that 134 farmers use 21 fungicides with 18 active ingredients on a total area of 35.2 hectares. In all, 18 fungicides with an EIQ at the level of “unlikely to be hazardous” (EIQ < 25) are used on about 95% of the acreage, and 3 fungicides with an EIQ of “slightly hazardous” (25 < EIQ < 50) are used on the rest of the area. The Field Use EIQ of fungicide was rated very low in only 8.2% of the survey area and moderate in 48%. Areas with high and very high ratings account for 3% and 41%, respectively. Using fungicides according to the instructions can reduce the Field Use EIQ values in cultivated areas by 38% and return areas with high and moderate ratings to a low rating. Therefore, it is necessary to instruct farmers on the safe use of fungicides and to recommend those with low EIQ values for chrysanthemum cultivation

Effects of hormone and fertilizers on early flower induction of Dendrobium anosmum hybrid seedlings under ex vitro condition

Early flowering of new orchids is important to save time for selecting valuable flowers and artificial induction of flowering is a critical consideration in the orchid production industry. In this study, a new Dendrobium anosmum hybrid was generated by cross-breeding between D. anosmum ‘Chau Nhu’ and D. anosmum ‘Di Linh’. The ancestors and hybrid seedlings from in-vitro culture were trained in the net house and their growth and flowering were evaluated under ex vivo conditions with specific fertilizers and hormones. The results suggest that the hybrid plants grew better than their parents in terms of stem height, stem diameter, and leaf number. Growth hormones were applied to stimulate early flowering in matured hybrids and it was discovered that ‘Keiki pro’, a commercial hormone product, produced the best results, with a flowering rate of 66.67% after two applications. Hybrid flowers varied in width from 36.36% (3.0-6.0 cm) to 63.64 % (more than 6.0 cm) from ancestral width in medium-sized and large-sized flowers, respectively. Also, the hybrid flower colours was mostly a combination of pink/violet (75C) and purple/pink (68A), which is different from their parents. Importantly, the dorsal sepal, petal colours, and shape of hybrid flowers varied significantly among individual hybrids, between hybrids and their progenitors. Some mutations in the lips and columns of the novel hybrid flowers were also visualized. Hence, the D. anosmum hybrid seedlings successfully induced flowers after a year of culture under optimal hormones and fertilizers conditions. The results can serve as a critical reference for the early flowering of the orchid seedlings

Ownership Concentration and Accounting Conservatism: The Moderating Role of Board Independence

The purpose of this study is to examine the moderating effect of board independence on the relationship between ownership concentration and accounting conservatism. Using fixed-effect regressions for a sample of 165 Vietnamese listed companies from 2007 to 2017, the results revealed that the proportion of outstanding shares owned by the largest shareholder is negatively associated with accounting conservatism and board independence plays a moderating role in this relationship. Our results are robust after applying alternative measures of the largest ownership and correcting for potential endogeneity using fixed-effects regression with instrumental variables. Overall, our evidence shows that firms with concentrated ownership should keep a high non-executive ratio to maintain accounting conservatism. In other words, increasing the number of non-executive directors on boards in firms with a substantial proportion of shares held by the largest shareholder is likely to strengthen the information environment, giving financial reporting more credibility.JEL Classification: G30; G32. Doi: 10.28991/ESJ-2023-07-01-07 Full Text: PD

Does academic procrastination mediate the link between Facebook addiction and academic satisfaction?

Purpose: Earlier studies suggested a link between Facebook addiction and life satisfaction among university students, but the association between it and academic satisfaction and their inner influencing mechanisms still needs to be clarified. This study investigated a mediation model between Facebook addiction and academic satisfaction, with academic procrastination as a mediator. Methods: A sample of 710 students (M = 18.80, SD = 0.8; 61.5% are female) from a university in Vietnam completed measures of Facebook addiction, academic procrastination, and academic satisfaction. Simple mediation analyses were conducted using PROCESS (Model 4) to calculate the indirect effects of Facebook addiction on academic satisfaction through academic procrastination. Findings: The results indicated that Facebook addiction was positively associated with academic satisfaction among university students, and academic procrastination partially mediated the association between Facebook addiction and academic satisfaction among university students. Conclusion: These findings provide a better understanding of the relationship between Facebook addiction, academic procrastination, and academic satisfaction, which may guide targeted interventions to improve academic satisfaction among university students

Phenolic compounds from leaves of Amensiodendron chinese (Sapindaceae)

From the ethyl acetate extract of the leaves of Amensiodendron chinense (Merr.) Hu (Sapindaceae), we isolated three known phenolic compounds: 4-hydroxy-3-methoxybenzaldehyde (1), methyl 3,4-dihydroxybenzoate (2), and 3,4-dihydroxybenzoic acid (3). We elucidated their chemical structures from the spectral data and compared them with those reported in the literature.3 hợp chất phenolic được phân lập từ cao chiết ethyl acetate của lá thuộc loài Amensiodendron chinese (Merr.) Hu (Sapindaceae) bao gồm : 4-hydroxy-3-methoxybenzaldehyde (1), methyl 3,4-dihydroxybenzoate (2), 3,4-dihydroxybenzoic acid (3). Cấu trúc hóa học được xác định dựa vào dữ liệu phổ và so sánh với tài liệu tham khảo

Investigating the diversity of arbuscular mycorrhizal fungi from Gymnema sylvestre and Curcuma longa in Vietnam

Arbuscular mycorrhizal (AM) fungi are soil eukaryotes that belong to phylum Glomeromycota and have symbiosis with the vast majority of higher plants’ roots. AM fungi are believed to be coevolved with terrestrial plants, the abundance and diversity of AM fungal communities as a result are host plant dependent. A survey of AM fungi from the rhizospheres of medicinal plants in Northern Vietnam including gurma Gymnema sylvestre and turmeric Curcuma longa was carried out. From the extracted total DNAs of the medicinal plants’ rhizosphere soil samples, 35 mycorrhizal fungal species were identified by analyzing small subunit rRNA gene sequences. Result revealed that genus Glomus is the most abundant in the AM communities of G. sylvestre and C. longa, followed by Gigaspora and Acaulospora. Besides, AM species belonging to genera Scutellospora, Diversispora and Rhizophagus were observed in almost all rhizosphere soil samples. The spore counting by wet sieving and decanting method uncovered a variation in AM spore density of gurma and turmeric rhizosphere. In general, AM species were found more abundantly and more diverse in collected rhizome soil samples of C. longa (27 species belonging to 10 genera) than of G. sylvestre (17 species found belonging to 7 genera). The observed difference in AM communities of G. sylvestre and C. longa supports evidence for the dependence of AM fungal species on host plants, and indicates that AM fungi may have relation to the host plants’ secondary metabolite production

LIGNANS FROM LEAVES OF AMESIODENDRON CHINENSE AND THEIR CYTOTOXIC ACTIVITY

ABSTRACTFrom leaves of Amesiodendron chinense (Mer.) Hu four lignans (+)-aptosimon (1), (+)-isolariciresinol (2), (-)-cleomiscosin A (3), and (-)-cleomiscosin C (3) were isolated. Their structures were determined by spectroscopic analysis including MS, 1D and 2D NMR as well as by comparison with reported data in literature. All compounds were evaluated for cytotoxic activities against five human cancer cell lines, KB, SK-LU-1, MCF-7, HepG-2, and SW-480. They showed weak cytotoxic activity on five tested human cancer cell lines with IC50 values ranging from 32.61 to 95.18 µg/ml

ĐẶC ĐIỂM KHÁNG KHÁNG SINH CỦA VI KHUẨN STREPTOCOCCUS SUIS PHÂN LẬP TỪ LỢN BẢN ĐỊA NUÔI TRÊN ĐỊA BÀN HUYỆN A LƯỚI, TỈNH THỪA THIÊN HUẾ

Streptococcus suis (S. suis) is a Gram-positive bacterium, a common cause of disease in pigs, and is a zoonotic pathogen. The objective of this study was to determine the infection rate, and antimicrobial resistance characteristics of S. suis isolated from local pigs in A Luoi district, Thua Thien Hue province. S. suis was isolated using on blood agar, and identified by PCR method; the antimicrobial resistance was assessed by disk diffusion method and the antimicrobial resistance genes were detected by PCR. The results showed that 33,33% of the samples were positive for S. suis. Most of S. suis isolates were susceptible to neomycin, gentamicin, and erythromycin; but resistant to penicillin, amoxicillin, ampicillin, and tetracycline. The results also showed that, amoxicillin and tetracycline resistance were significantly positively correlated with penicillin resistance; enrofloxacin and gentamicin were significantly negatively correlated with penicillin and ampicillin. A high percentage of S. suis isolates carried gyrA and parC genes (75.61%), Sul1 (70.73%), and ermB (29.27%). There was 92.68% of S. suis isolates showed multidrug resistance and 82.93% of the isolates carried multiple antimicrobial resistance genes.Streptococcus suis (S. suis) là vi khuẩn Gram dương gây bệnh ở lợn và có thể lây sang người. Mục tiêu của nghiên cứu là xác định tỷ lệ nhiễm, đặc điểm kháng kháng sinh của S. suis phân lập được từ lợn bản địa ở A Lưới, Thừa Thiên Huế. S. suis được phân lập trên môi trường thạch máu, định danh bằng phương pháp PCR; kháng kháng sinh được đánh giá bằng phương pháp khuếch tán trên thạch và gene kháng kháng sinh được phát hiện bằng phương pháp PCR. Kết quả cho thấy, có 41/123 (33,33%) con bị nhiễm S. suis. Tỷ lệ cao chủng S. suis nhạy cảm với streptomycin, neomycin, gentamicin và erythromycin; nhưng cũng có tỷ lệ cao đã kháng lại penicillin, amoxicillin, ampicillin và tetracycline. Mối tương quan chặt chẽ giữa tính kháng với amoxicillin và penicillin; tetracycline và penicillin; giữa tính nhạy cảm với enrofloxacin và tính kháng lại penicillin; giữa tính nhạy cảm với gentamicin và tính kháng với ampicillin của các chủng S. suis đã được phát hiện. Tỷ lệ cao các chủng S. suis mang gene gyrA và parC (75,61%), Sul1 (70,73%), và ermB (29,27%). Có 92,68% số chủng S. suis kháng lại nhiều loại kháng sinh và 82,93% chủng mang nhiều gene kháng kháng sinh

Phytoplankton community structure and water quality of Red River, Vietnam

This study aimed to describe the distribution and relative abundance of the phytoplankton obtained during the two seasons (rainy and dry seasons) from the Red river system. The water and phytoplankton samples were monthly collected during the year 2012 at four sampling stations along the Red River (Yen Bai, Vu Quang Hoa Binh,and Ha Noi) . Environmental variables (e.g. temperature, dissolved oxygen, pH, suspended solids, conductivity, TDS, NO3­-N, NH4­-N, PO4-P, Total Phosphorus; and DOC) and phytoplankton (e.g. cell density and relative abundant species) were analyzed. Six phytoplankton classes were identified with the Bacillariophyceae dominating in the phytoplankton community. A distinct seasonal variation in phytoplankton structure was observed with high cells density in dry season and low values in rainy season. PCA (Principal Component Analysis) showed that suspended solid factor that governed the temporal and spatial distribution of phytoplankton structure in the Red River system.Nghiên cứu này trình bày sự phân bố và độ phong phú tương đối của quần xã thực vật nổi vào mùa mưa và mùa khô trong hệ thống sông Hồng. Các mẫu nước và thực vật nổi được thu hàng tháng trong năm 2012 tại 4 điểm trên sông Hồng (Yên Bái, Vụ Quang, Hòa Bình và Hà Nội). Các thông số môi trường (nhiệt độ, lượng oxy hòa tan, pH, chất rắn lơ lửng, độ dẫn, TDS, NO3-N, NH4-N, PO4-P, T-P và DOC) và thực vật phù du (mật độ tế bào,độ phong phú tương đối ) đã được phân tích. Sáu lớph tảo được được xác định với tảo silíc chiếm ưu thế trong quần xã thực vật phù du. Sinh khối thực vật đạt giá trị cao vào mùa khô trong khi thấp vào mùa mưa. Phân tích hợp phần chính cho thấy yếu tố chất rắn lơ lửng đóng vai trò quan trọng việc xác định biến động thời gian và không gian cấu trúc quần xã thực vật nổi trong hệ thống sông Hồng