Factors affecting intention to purchase organic agriculture products among Vietnamese

Globally, customer intention to purchase has become the essential part of the product and organization's success in the market. More recently, the idea has captured the attention of academic and policymakers alike. Therefore, the current article analyses product quality features such as agreeableness, emotional stability conscientiousness, openness to experience and extroversion on the intention to purchase organic agricultural products in the context of Vietnam. The study also analyses the mediating role of customer satisfaction between the association of product quality features and intention to purchase organic products in Vietnam. The present study uses questionnaires to collect data pertaining to the health sector of Vietnam. The current study employs the smart-PLS to analyze the constructs and items' reliability as well as the association among constructs. The results show that product quality features except extroversion have a positive and significant association with intention to purchase organic products in Vietnam. The results also reveal that customer satisfaction significantly and positively mediates among the associations of product quality features and intention to purchase organic products in Vietnam. This study is suitable for policymakers while formulating policies that may directly or indirectly affect customers' intention to purchase organic agricultural products.Luong Thu Thuy (Faculty of Economics, Academy of Finance, Vietnam), Tran Thi Phuong Diu (Faculty of Economics, Academy of Finance, Vietnam), Nguyen Dinh Hoan (Faculty of Economics, Academy of Finance, Vietnam), Vu Viet Ninh (Faculty of Economics, Academy of Finance, Vietnam), Nguyen Thi Thuy Nga (Faculty of Economics, Academy of Finance, Vietnam)Includes bibliographical reference

Estimation of errors in determination of main parameters of earthquake hypocenter, recorded by the national seismic network of Vietnam

In this paper the authors present the error estimation in determining main parameters of earthquake hypocenter based on solving the system of linear equations, expressing the relationship between earthquake coordinates and the coordinates of the seismic stations. The results of the error estimation in determining the epicenter coordinates and the focus depth of the earthquakes recorded by the system of 30 seismic stations in Vietnam are presented, interpreted and compared with the results of the previous studies.The results show that the operation of the seismic network of Vietnam is not really optimal, particularly when determining the epicenter coordinates and the focus depth of the earthquakes in the East Vietnam Sea region.The national seismic network of Vietnam allows determination of the epicenter coordinates and the focal depth of earthquakes for most of the Vietnam territory with the errors ∆h ≤ 20 km, ∆φ ≤ 4 km, ∆ ≤ 5 km. The errors of the determination of the epicenter coordinates and the focal depth of the earthquakes are increasing to the south and southwest areas of the territory of Vietnam and reach the maximum in these areas. Particularly, errors of the determination of the epicenter coordinates (∆φ, ∆λ) and the focal depth (∆h) of earthquakes increase very rapidly toward the East Sea of Vietnam and reach the maximum in the region between the longitudes of 116-118°E.The Vietnam seismic network allows determining the epicenter coordinates and the focal depth of earthquakes in the Northern Vietnam with the smaller errors than in Central and Southern Vietnam, and this fact proves that the distribution of seismic network in Northern Vietnam is more optimal than the station networks in the Central and Southern Vietnam. Therefore, in order to improve the effectiveness of the Vietnam seismic network, more seismic stations need to be added to the Central and Southern Vietnam.References Aranovich Z.I., 1980. On the method of selecting the optimal positions of seismic stations in the local network. //Methodologies and assessment results of the effectiveness of the regional seismic network. Tbilisi: Mesnhiereba, 150-157 (in Russian).Aranovich Z.I., Akhalbedasvili А.М., Gosadze О.D. et al., 1977. The methodologies of evaluating the effectiveness of regional seismic network, in case of the Caucasus region.//The issues of optimization and automation of seismic observations. Tbilisi: Mesnhiereba, 27-57 (in Russian). Bui Van Duan, Nguyen Cong Thang, Nguyen Van Vuong, Pham Dinh Nguyen, 2013. The magnitude of the largest possible earthquake in the Muong La-Bac Yen fault zone. J. Sci. of the Earth, 35, 53-49.Burmin V. Yu.,  1976. The task of experimental planning and the estimation of the system of linear algebraic equations.//The USSR Academy of Sciences Publishing House. Cybernetics, 2, 195-200. Burmin V. Yu., 1986. The optimal distribution of seismic stations when recording near earthquakes.//The USSR Academy of Sciences Publishing House. Geophysics. Moscow, 5, 34-42 (in Russian).Burmin V. Yu., Akhmechiev V.M., 1994. The errors in determining parameters of near earthquake hypocenter and the effectiveness of seismic network.//Journal of Volcanology and Seismology. Moscow, 2, 109-128 (in Russian).Burmin V. Yu., Ngo TL., Kondorskaia N.V. and Akhmechiev V.M., 1992. The geometric analysis of existing seismic network in the Northern Vietnam.//The news from Russian Academy of Sciences. Journal of Geophysics. Moscow, 6, 123-128 (iIn Russian).Burmin V. Yu., Ngo T.L., Tran V.P., 2009. Estimation of efficiency of seismic stations modern network and design of an optimal one on the territory of Vietnam.// Journal “Seismic Instruments”, 45(1), 27-35.Burmin V. Yu., Nguyen VP., 2001. Planning to optimum regional network of the seismological observations for South- East Asia.//Journal “Volcanology and Seismology”, 1, 68-75.Iosif T. and Iosif S., 1974. Optimization of seismic stations distribution in Romania.//Studii si cercetari de geofisica, 12, 51-88.Iosif T., Skoko D. and Sato Y., 1972. Optimum distribution of seismic stations in Romania.//Bull. Int. seism. Earthq. Eng, 9, 121p.Kijko A., 1975. On optimal extensions of regional networks of seismic stations - Publs. Inst. Geophys. Pol. Acad. Sci., 96, 57-119.Kijko A., 1978. Method of the optimal planning of regional seismic networks.//Polish Academy of Sci. publication of the inst. Of geoph. A-7 (119). Panctwowe wydawnictwo naukowe. Warszawa; Lodz, 63p.Kijko A., 1980. Optimum seismic networks in the Ostrova coal basin.//Czechoslovakia. Acta montana UGG CSAV. Praha, 55, 73-95.Marshall A.W., Olkin I., 1965. Norms and inequalities for condition numbers.//Pacific J. Math, 15, 241-247.Marshall A.W., Olkin I., 1969. Norms and inequalities for condition numbers.//Linear Algebra and Application, 2(2), 167-172.Marshall A.W., Olkin I., 1973. Norms and inequalities for condition numbers.//Linear Algebra and Application, 3(7), 191-300.Ngo TL., 1990. Kinetic and dynamic parameters of earthquake hypocenter in the Northern Vietnam. The Candidate of Sciences Thesis on Mathematics-Physics, Speciality Geophysics. Institute of Geophysics, the USSR Academy of Sciences. Moscow, 133p (in Russian).Ngo T.L., 1999. The characteristics of seismicity and the main features of earthquake hypocenter in the Southeast Asia from the viewpoint of clarifying the new tectonic structures. The Doctor of Science Thesis on Mathematics-Physics, Speciality Geophysics. Institute of Geophysics, the USSR Academy of Sciences. Moscow, 342p (in Russian).Ngo T.L., 2005. The algorithm for improvement of velocity model of Earth’s crust and hodographs of travel times of seismic waves in the territory of Vietnam. J. Sci. of the Earth, 27(1), 23-26.Ngo T.L., 2005. The analysis of the seismic data for accounting hodographs of travel times of P-wave. J. Sci. of the Earth, 27, 374-377.Ngo T.L., Tran V.P., Vu T.H., Le T.T., 2014. The establishment of velocity model and hodographs of travel times of seismic waves in the Earth’s crust in the Northern, Central and Southern regions of Vietnam. Journal of Geology, Hanoi, Series A, 341-345, 355-365.Nguyen Quy Hy, et al., 1979. Optimal addition of seismic network in the Vietnam territory by the method of seismic experimental planning.//The research results of “Earth Sciences” 1977-1978. Series Geophysics. Vietnam Academy of Science and Technology. Hanoi, 9-31 (in Vietnamese).Nguyen Van Hung., Hoang Quang Vinh, Nguyen Van Huong, 2016. Tectono-structural system and geodynamic features of Northwest Vietnam in the late Cenozoic period. Vietnam J. Earth Sci., 38(1), 38-45. Doi: 10.15625/0866-7187/38/1/8408.Sato Y., 1965. Optimum distribution of seismic observation points.//Zisin J. Seism. Soc. Japan, 18(1), 9-14.Sato Y., Skoko D., 1965. Optimum distribution of seismic observation points II.//Bull. Earthquake. Res. Inst., 43(3), 451-458.Sato Y., Ochi I., 1967. Accuracy of the determination of earthquake source parameters in and around Japan.//Bull. Earthq. Res. Inst., 45(1), 1-17.Savarenski E.F., Shafronov V.V., Peskov A.B. et al., 1979. Optimal planning of seismic stations from the viewpoint of minimizing error in the epicenter determination.//The USSR Academy of Sciences Publishing House, 8, 64-71 (in Russian).Skoko D., Kotake Y., Sato Y., 1968. Optimum distribution of seismic observation points. V//Bull. Earthquake. Res. Inst., 46(4), 821-840.Skoko D., Sato Y., Ochi I., Dutta T.K., 1966. Accuracy of the determination of earthquake source parameters as determined by Monte Carlo method: Observation on Indian Network.//Bull. Earthquake. Res. Inst., 44(3), 893-900.  

Preparation of some new benzo[d]thiazole derivatives

In this work, four new benzo[d]thiazole derivatives were synthesized successfully from vanillin. Nitration of vanillin gave nitrovanillin followed by cyclization reaction with o-aminothiophenol under microwave irradiation in 4 minutes to give nitroaromatic compound 3. The reduction to convert the nitro group to amino group was optimized. It was found that Fe/ con. HCl in ethanol was the best condition for this case about both yield (~95 %) and simple procedure to give compound 4 as a salt. Acetylation occurs at both phenolic hydroxyl group and amino group of the salt 4 to form N,O-acetyl compound 5. Under mild hydrolysis 5 produces N-acetyl compound 6. The structures of these compounds were established by IR, 1H and 13C NMR and mass spectral analyses. Keywords. benzo[d]thiazole, vanillin, reduction, microwave

Algorithm and program for earthquake prediction based on the geological, geophysical, geomorphological and seismic data

By applying an improved  method of the Earth's crust classification, we develop an algorithm and build an earthquake prediction program using a combination of geological, geophysical, geomorphological and seismic data.This program includes a system of multiple windows with different functions, which can divide fault zones into the different segments by the maximum magnitude values Mmax. Using the constructed program, we carried out an earthquake prediction test for the Northwest Vietnam by a combination of geological, geophysical, geomorphological and seismic data. According to the received results, zoning maps of maximum earthquake prediction for the researched region has been established. The results show that the   areas, capable of generating earthquakes with Mmax = 6.5 - 6.8  are primarily concentrated along some major fault zones such as Lai Chau-Dien Bien, Son La, Song Ma, Song Da, Tuan Giao or near the intersection of these fault zones. The received results show a good accordance with the actual seismotectonic characteristics of the researched region.References Bui Van Duan, Nguyen Cong Thang, Nguyen Van Vuong, Pham Dinh Nguyen, 2013. The magnitude of the largest possible earthquake in the Muong La - Bac Yen fault zone. Journal of Sciences of the Earth 35, 53-49.Cao Dinh Trieu, 1999. Probable approach for long-term earthquake prediction in Vietnam based on the regulation of epicentral distribution. Journal of Geology, Series A (251), 14-21, Hanoi (in Vietnamese).Cao Dinh Trieu, Nguyen Huu Tuyen, Thai Anh Tuan, 2006. The correlation between the structure of the Earth’s crust and seismic activities in the Northwest region of Vietnam”. Journal of Sciences of the Earth, 28, 155-164, Hanoi (in Vietnamese).Cao Dinh Trieu, Ngo Thi Lu, Cao Xuan Bach et al., 2007. Prediction of maximum earthquake occurrence in Vietnam on the basis of crustal characteristics”. Proceedings of the 5th Vietnam’s Scientific Conference on Geophysics, 159-171, Science and Technics Publishing House, Hanoi (in Vietnamese).Dang Thanh Hai, Nguyen Duc Vinh, Cao Dinh Trieu, 2002. Long-term earthquake prediction in Lai Chau-Dien Bien region on the basis of time - magnitude model. Journal of Science and Technology, 40(4), 45-53, Hanoi (in Vietnamese).Dang Thanh Hai, 2003. Study on deep structures of the Earth’s crust and seismotectonic zoning in Northern Vietnam. Physics Ph.D. Thesis, 170p, Hanoi (in Vietnamese).Grishin A.P., 2001. The statistical model for predicting the occurrence time and magnitude of the earthquake”. Journal of Volcanology and Seismology (4), 60-65, Russian Academy of Sciences, Moscow. (in Russian).Grishin A.P., N.V. Kondoskaya, L.E. Levin, L.N. Solodinov, A.L. Petrov, O.M. Petrov, 2001. “Experiment of statistical prediction in Kaspi region (occurrence time, epicenter coordinate and magnitude value of the earthquake). Geophysics in the 21th century, The 3rd Collection of Reading Materials on Geophysics, Scientific World, 149-156.Gubin I.E., 1950. The method of seismotectonic zoning. The projects of The Geophysical Center, Russian Academy of Sciences, 13.Gumbel E.J., 1958. Statistics of Extremes”. Columbia Univ. Press.Gutenberg B. and G.F. Richter, 1954. Seismicity of the Earth and associated phenomena. Princeton Univ. Press.Ngo Thi Lu, Tran Viet Phuong, 2012. About the approach to building algorithms and processes to predict earthquakes by statistical model. Journal of Sciences of the Earth, 34(4), 535-541.Ngo Thi Lu, Tran Viet Phuong, 2013. Building a new algorithm of the program for separation of forshock and aftershock groups from earthquake catalog to ensure the independence of the events. Journal of Marine Science and Technology. 3A(13), 79-85.Ngo Thi Lu (Project manager), 2011. Assessment of the seismic potential in Vietnam based on a combination of geological, geophysical and seismic data”. The international scientific cooperation between Vietnam Academy of Science and Technology and Russian Academy of Sciences under the state-level protocol (2008-2010), Final Report, 163p, Hanoi (in Vietnamese).Ngo Thi Lu (Project manager), 2013. Establishment of experimental program for short-term earthquake prediction based on the statistical model combined with tectonophysics in Vietnam and adjacent regions. The independent project of Vietnam Academy of Science and Technology, Code VAST.DL.09/11-12, 125p, Hanoi (in Vietnamese).Nguyen Hong Phuong, 1991. Probabilistic assessment of earthquake hazard in Vietnam based on seismotectonic regionalization. Tecronophysics, 198, 81-93.Nguyen Hong Phuong, 1997. Evaluation of the maximum earthquake for seismic source zones in Vietnam by a combination of probability methods. The scientific works on geology and marine geophysics (3), 48-65, Science and Technics Publishing House, Hanoi (in Vietnamese).Nguyen Hong Phuong, 2001. Probabilistic Seismic Hazard Assessment Along the Southeastern Coast of Vietnam, Natural Hazards 24, 53-74.Nguyen Hong Phuong, Pham The Truyen, 2014. Probabilistic Seismic Hazard Assessment for the South Central Vietnam. Vietnam Journal of Earth Sciences 36, 451-461.Nguyen Dinh Xuyen (Project manager), Nguyen Ngoc Thuy et al., 1996. Database of earthquake mitigation measures in Vietnam. The final report of state-level independent project, Code KT-DL 92-07, 3 volumes, Institute of Geophysics, Hanoi (in Vietnamese).Nguyen Dinh Xuyen, 2002. Earthquake and earthquake hazard level. Internal document, Institute of Geophysics, Hanoi (in Vietnamese).Nguyen Dinh Xuyen, Pham Dinh Nguyen, Pham Quang Hung, Nguyen Anh Duong, 2003. Experiment of long-term earthquake prediction based on the mechanism of foreshock activities. Journal of Sciences of the Earth, 25(3), 193-200, Hanoi (in Vietnamese).Phan Trong Trinh, Ngo Van Liem, Nguyen Van Huong, Hoang Quang Vinh, Bui Van Thom, Bui Thi Thao, Mai Thanh Tan, Nguyen Hoang, 2012. Late Quaternary tectonics and seismotectonics along the Red River fault zone, North Vietnam. Earth-Science Reviews 114(3), 224-235.Phan Trong Trinh , Hoang Quang Vinh, Nguyen Van Huong, Ngo Van Liem, 2013. Active fault segmentation and seismic hazard in Hoa-Binh reservoir, Vietnam. Cent. Eur. J. Geosci. 5(2), 223-235.Pham Van Thuc and Kijko, A., 1985. Estimation of maximum magnitude and seismic hazard in Southeast Asia and Vietnam. Acta Geophys. Pol., XXX111 (4), 377-387.Pham Van Thuc, 2007. Seismology and earthquake in Vietnam. The monographs on natural resources and environment in Vietnam, Publishing House for Science and Technology, Vietnam Academy of Science and Technology, 378p (in Vietnamese).Reisner G.I., L.I. Ioganson, M.G. Reisner, Iu.E. Baranov, 1993. Characteristic classification of the Earth’s crust and the modern geological process. Publishing House of Russian Academy of Sciences, Moscow, 210p (in Russian).Reisner G.I., L.I. Ioganson, 1996. The Extraregional Seismotectonic Method for the Assessment of Seismic Potential. Natural Hazards 14, 3-10 (Kluwer Academic Publishers, printed in the Netherlands).Tran Thi My Thanh, 2002. Assessment of seismic hazard in Vietnam and adjacent regions. Physics Ph.D. Thesis, 161 pages, Hanoi (in Vietnamese).Vu Thi Hoan, Ngo Thi Lu, M.V. Rodkin, Tran Viet Phuong, 2014. Application of the generalized extreme value distribution to study the seismicity of the Southeast Asian. Journal of Geology. Series A, 341-345. Hanoi. 

The Association Between Ambient Temperatures and Hospital Admissions Due to Respiratory Diseases in the Capital City of Vietnam

This study aimed to examine the short-term effects of ambient temperature on hospital admissions due to respiratory diseases among Hanoi residents. We collected 34,653 hospital admissions for 365 days (November 1, 2017, to November 31, 2018) from two hospitals in Hanoi. A quasi-Poisson regression model with time series analysis was used to explore the temperature-health outcome relationship's overall pattern. The non-linear curve indicated the temperatures with the lowest risk range from 22 degrees (Celcius) to 25 degrees (Celcius). On average, cold temperatures showed a higher risk than hot temperatures across all genders and age groups. Hospital admissions risk was highest at 13 degrees (Celcius) (RR = 1.39; 95% CI = 1.26–1.54) for cold effects and at 33 degrees (Celcius) (RR = 1.21, 95% CI = 1.04–1.39) for the hot effects. Temporal pattern analysis showed that the most effect on respiratory diseases occurred at a lag of 0 days for hot effect and at a lag of 1 day for cold effect. The risk of changing temperature among women and people over 5 years old was higher than other groups. Our results suggest that the risk of respiratory admissions was greatest when the temperature was low. Public health prevention programs should be enhanced to improve public awareness about the health risks of temperature changes, especially respiratory diseases risked by low temperatures

EFFECT OF PRO-OXIDANT ADDITIVES ON DEGRADATION OF MULCH FILM BASED ON RECYCLED POLYETHYLENE

The effect of pro-oxidant additives (Iron, Cobalt and Manganese stearates) on the biodegradation of recycle polyethelene mulching films was studied in both accelerated weather and natural exposure conditions. The degradation degree of film was determined by measuring mechanical properties and scanning electronic microscope (SEM). The results showed that the mechanical properties of film samples with pro-oxirant additives decreased rapidly, and that surface film with additives was degraded clearly compared to the films without additives after 30 cycles of accelerated weather. Reliability in terms of acceleration are 28 - 30 cycles of exposure and in the natural conditions reached 10-12 months

ĐẶC ĐIỂM DÒNG CHẢY VEN BỜ BẮC TRUNG BỘ (HÀ TĨNH - THỪA THIÊN-HUẾ) THỜI KỲ 4/2016

This paper presents the modeled results of general current pattern (daily average value) in Northern Central Vietnam Coast (Ha Tinh - Thua Thien-Hue) during April 2016. Study results show that in general, current flowed from the North to the South with small and instable velocity (V ≈ 0.1 - 0.2 m/s). From 2nd to 6th April current flowed from the South to the North. From 7th to 29th April current flowed from the North to the South. During 13rd to 16th April current velocity was weak (V ≤ 0.1 m/s). In the southern region of Thua Thien-Hue province, the direction of current was instable (from 6th to 9th and from 20th to 22nd April current flowed from the South to the North). Current distribution pattern from modeled results was in accordance with the propagation characteristics of surface water temperatures in the studied area through data analysis of satellite images.Bài báo trình bày kết quả tính toán trường dòng chảy tổng hợp trung bình ngày cho khu vực ven bờ Bắc Trung Bộ (Hà Tĩnh - Thừa Thiên-Huế) thời kỳ 4/2016. Kết quả nghiên cứu cho thấy trong thời gian nghiên cứu nhìn chung dòng chảy tổng hợp trung bình ngày có hướng từ bắc xuống nam, tốc độ tương đối nhỏ V ≈ 0,1 - 0,2 m/s và không ổn định. Từ 2-6/4/2016 dòng chảy tổng hợp trung bình ngày ven bờ có hướng từ nam lên bắc. Từ 7-29/4/2016 dòng chảy ven bờ có hướng từ bắc xuống nam. Các ngày 13-16/4/2016 dòng chảy tổng hợp trung bình ngày có tốc độ nhỏ (V ≤ 0,1 m/s). Khu vực phía nam Thừa Thiên-Huế dòng chảy tổng hợp trung bình ngày có hướng bị biến động mạnh nhất (các ngày 6-9/4 và 20-22/4 hướng dòng từ nam lên bắc). Đặc điểm phân bố dòng chảy tính toán tương đối phù hợp với đặc điểm lan truyền nhiệt độ nước tầng mặt tại khu vực nghiên cứu qua số liệu phân tích ảnh vệ tinh