Pesticide Use and Management in the Mekong Delta and their Residues in Surface and Drinking Water

Pesticides are essential inputs in agricultural production to control target pests and thus to improve crop yields. Appropriate use and management of these chemicals and reduction of its negative influences on human health and the environment are global concerns. In the Mekong Delta, Vietnam, an area which contributes more than 90% to the country’s rice exports, pesticides have been increasingly applied since the so called Doi Moi (renovation). In this present study, two representative areas were selected to conduct different studies related to 1) pesticide use and management at household level, 2) resulting residue concentrations in surface water in fields and irrigation canals, 3) treatment practices of surface water for the purpose of drinking, and 4) pesticide concentrations in drinking water derived from surface water. One study area is characterized by intensive rice cultivation in Tam Nong District, Dong Thap Province, while the second area was selected as a representative for a peri-urban site mixed agricultural production pattern in Cai Rang District, Can Tho City. Surveys and monitoring campaign were carried out from August 2008 to August 2009. Survey results indicated that a majority of respondent farmers improperly used and managed pesticides. The study found that organochlorine and organophosphorus pesticides were less used while several pesticide groups such as pyrethroid, conazole, biopesticide and amide were being frequently applied. Half of investigated pesticides belong to moderately and slightly hazardous categories according to WHO hazard classification. 12 out of 15 studied pesticides (buprofezin, butachlor, cypermethrin, difenozonazole, α-endosulfan, β-endosulfan, endosulfan-sulfate, fenobucarb, fipronil, hexaconazole, isoprothiolane, pretilachlor, profenofos, propanil and propiconazole) were quantified in surface water in fields and irrigation canals, with average concentrations ranging from 0.02 to 3.34 μg/L and from 0.01 to 0.37 μg/L at the intensive rice cultivation and mixed agricultural production areas, respectively. Monitoring of pesticide residues in drinking water quantified seven out of 15 studied pesticides, with average concentrations ranging from 0.01 to 0.47 μg/L. The study also revealed that aluminium sulfate and boiling practice, frequently applied to treat surface water for drinking by respondent farmers, unfortunately could not remove the most of studied pesticides from drinking water. Consequently, as compared to European Commission guideline values for drinking water local people were exposed to several pesticides which might pose their health at risk. The present study provides and discusses possibly measures in order to improve pesticide management practices as well as to decrease pesticide inputs into water ecosystems and thus reduce the exposure of (rural) people to these potentially harmful chemicals

Co-simulation of self-adjusting fuzzy PI controller for the robot with two-axes system

This paper presents the co-simulation of the self-adjusting fuzzy PI controller to control a two-axes system. Each axis was driven by a permanent magnet linear synchronous motor (PMLSM). The position and speed controller used the fuzzy PI algorithm with parameters adjusted by a radial basis function neural network (RBFNN). The vector control was applied to the decoupled effect of the PMLSM. The field programmable gate array (FPGA) was used to control both axes of the system. The very high-speed integrated circuit-hardware description language (VHDL) was developed in the Quartus II software environment, provided by Altera, to analyze and synthesize designs. Firstly, the mathematical model of PMLSM and fuzzy PI was introduced. Secondly, the RBFNN adjusted the knowledge base of the fuzzy PI. Thirdly, the motion trajectory was introduced for testing the control algorithm. Fourthly, the implementation of the controller based on FPGA with the FSM method and the structure of co-simulation between Matlab/Simulink and ModelSim were set up. Finally, discussion about the results proved the effectiveness of the control system, determining the exact position and trajectory of the XY axis system. This research was successful in implementing a two-motor controller within one chip

しらすならびに石灰石微粉末がコンクリートの圧縮強度および化学抵抗性に及ぼす影響

広島大学(Hiroshima University)博士(工学)Doctor of Engineeringdoctora

Organic Fertilizer Production and Application in Vietnam

Crop production is an important subsector of Vietnam’s agriculture, has an impressive achievement in last 30 years and based on the intensive production with increasing use of chemical fertilizer and pesticide. Consequences are the negative effects on environment and human health and food safety. Organic agriculture has become a trend worldwide and is developing rapidly in the world. In Vietnam the certified organic farming area has expanded since 2012. Organic market revenue in Vietnam is estimated to be at $132.15 million a year. Most Vietnamese certified organic products are exported to international markets. Organic agriculture using organic fertilizer is one of Vietnam government’s priorities. Vietnam already produced organic fertilizer from different materials by using different production technologies, but the production capacity is small and does not meet the demand for organic agriculture. Vietnam government encourages, promotes the organic fertilizer production, application and has the policy to develop the organic fertilizer in Vietnam

Taxonomy of the genus Paris L. (Melanthiaceae) in Vietnam

Paris L. is a small genus distributed widely in Eurasia. In Vietnam Paris occur in evergreen broad-leaved forests in some mountainous areas of the North and the Central highlands. Due to over-exploitation as well as habitat loss, populations of some Paris species are seriously declining. This genus has not been studied extensively in Vietnam. The aim of this study was to define the morphological characteristics of the genus Paris in Vietnam. Morphological description, dichotomous key for identification, ecology and distributions of the genus in Vietnam are reported. The results show that this genus in Vietnam comprises 8 species and 2 varieties, possesing unilocular ovary with parietal placenta

An evaluation of economic viability of small scale slaughterhouses in Vietnam: Implication for pig value chain development

Slaughterhouse plays important role in pig value chain in Vietnam, not only for the functions it plays and economic added value it generates, but also for product quality relates to food safety standards that is much affected under slaughtering activity. The study is aimed to get a better understanding of structure, conduct, performance and economic viability of small scale slaughter houses in the pig value chain, and draw key implications for pig value chain development in Vietnam. Nghe An and Hung Yen are selected as study site. Data is collected from 51 small scale slaughterhouses in 18 communes. Descriptive and comparative statistics are employed with t-test for mean comparison. Results show that slaughterhouse plays multiple functions in the pig value chain, generate permanent jobs for at least 2 family labors, and provides an income of about 18 USD/working day for family labor, contributing about threefourths of total family income. Slaughtering activity generates an added value of 165 USD/one ton of live pig, accounting from 24%-44% total value added in the pig value chain. Upstream and downstream linkages of slaughterhouses in the chain are quite loose with no formal contract. The majority of small scale slaughterhouses do not meet the standards for pig slaughterhouse as required by the Ministry of Agriculture and Rural Development. The setting up as well as slaughtering practices are perceived to contribute to exposure of meat to contamination that could lead to higher incidence of salmonella in pork, a common cause of foodborne illness for consumers. Rising concerns of consumers about food safety as well as increasing level of economic integration of Vietnam are factors potentially having great impacts on economic viability of small scale slaughterhouse in Vietnam. Several recommendations for upgrading slaughterhouse are proposed accordingly

Induced systemic resistance against rice grassy stunt virus – a promising field for ecological rice production: Research article

Most rice protection methods have currently used toxic chemicals to control pathogens and pests, which leads to environmental pollution. Systemic acquired resistance (SAR) taking advantage of natural defence reaction of plants could be proposed as an alternative, ecologically friendly approach for plant protection. Its application into rice production could minimize the chemicals quantity used and could contribute to the decrease of environmental pollution and the development of sustainable agriculture. The research was conducted to select the most effective chemical and suitable method to improve the health of rice plants infected by grassy stunt disease in net-house of Can Tho University. SAR chemicals were used at very low concentrations (in mM). Results showed that the height of rice plants treated with SAR chemicals was higher than that of plants untreated. Besides, the number of diseased plants was reduced and the ratio of firm grain and yield increased when plants were applied by SAR. Among the used substances, oxalic acid provided the best systemic acquired resistance. With oxalic acid, seed soaking was better than seed coating in systemic acquired resistance against rice grassy stunt disease.Hầu hết các phương pháp sản xuất lúa hiện nay đều sử dụng các hóa chất độc hại trong việc phòng trừ bệnh và côn trùng gây hại, nên dẫn đến ô nhiễm môi trường. Kích thích tính kháng lưu dẫn giúp kích hoạt cơ chế tự nhiên kháng bệnh của cây có thể là giải pháp bảo vệ thực vật thay thế an toàn với môi trường. Việc ứng dụng tiến bộ này vào trong sản xuất lúa có thể làm giảm lượng hóa chất sử dụng, đóng góp vào việc giảm thiểu ô nhiễm môi trường và sự phát triển của một nền nông nghiệp bền vững. Nghiên cứu đã được thực hiện tại nhà lưới trường Đại học Cần Thơ để tuyển chọn hóa chất và phương pháp sử dụng hóa chất để tăng cường sức khỏe giúp cây lúa vượt qua bệnh vàng lùn. Hóa chất kích kháng được sử dụng ở một nồng độ rất thấp (đơn vị là mM). Kết quả cho thấy chiều cao cây lúa khi xử lý chất kích kháng tốt hơn so đối chứng không xử lý. Bên cạnh đó, số cây lúa nhiễm bệnh giảm, tỉ lệ hạt chắc và năng suất tăng khi cây lúa được xử lý với chất kích kháng. Trong số các chất kích kháng đã sử dụng, acid oxalic cho hiệu quả vượt trội. Với chất acid oxalic, phương pháp ngâm hạt cho hiệu quả kích kháng tốt hơn phương pháp áo hạt

Transformer-Based Deep Learning Detector for Dual-Mode Index Modulation 3D-OFDM

In this paper, we propose a deep learning-based signal detector called TransD3D-IM, which employs the Transformer framework for signal detection in the Dual-mode index modulation-aided three-dimensional (3D) orthogonal frequency division multiplexing (DM-IM-3D-OFDM) system. In this system, the data bits are conveyed using dual-mode 3D constellation symbols and active subcarrier indices. As a result, this method exhibits significantly higher transmission reliability than current IM-based models with traditional maximum likelihood (ML) detection. Nevertheless, the ML detector suffers from high computational complexity, particularly when the parameters of the system are large. Even the complexity of the Log-Likelihood Ratio algorithm, known as a low-complexity detector for signal detection in the DM-IM-3D-OFDM system, is also not impressive enough. To overcome this limitation, our proposal applies a deep neural network at the receiver, utilizing the Transformer framework for signal detection of DM-IM-3D-OFDM system in Rayleigh fading channel. Simulation results demonstrate that our detector attains to approach performance compared to the model-based receiver. Furthermore, TransD3D-IM exhibits more robustness than the existing deep learning-based detector while considerably reducing runtime complexity in comparison with the benchmarks