453 research outputs found

    Changes of benthic macroinvertebrates in Thi Vai River and Cai Mep Estuaries under polluted conditions with industrial wastewater

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    The pollution on the Thi Vai River has been spreading out rapidly over the two lasted decades caused by the wastewater from the industrial parks in the left bank of Thi Vai River and Cai Mep Estuaries. The evaluation of the benthic macroinvertebrate changes was very necessary to identify the consequences of the industrial wastewater on water quality and aquatic ecosystem of Thi Vai River and Cai Mep Estuaries. In this study, the variables of benthic macroinvertebrates and water quality were investigated in Thi Vai River and Cai Mep Estuaries, Southern Vietnam. The monitoring data of benthic macroinvertebrates and water quality parameters covered the period from 1989 to 2015 at 6 sampling sites in Thi Vai River and Cai Mep Estuaries. The basic water quality parameters were also tested including pH, dissolved oxygen (DO), total nitrogen, and total phosphorus. The biodiversity indices of benthic macroinvertebrates were applied for water quality assessment. The results showed that pH ranged from 6.4 – 7.6 during the monitoring. The DO concentrations were in between 0.20 – 6.70 mg/L. The concentrations of total nitrogen and total phosphorous ranged from 0.03 – 5.70 mg/L 0.024 – 1.380 mg/L respectively. Macroinvertebrate community in the study area consisted of 36 species of polychaeta, gastropoda, bivalvia, and crustacea, of which, species of polychaeta were dominant in species number. The benthic macroinvertebartes density ranged from 0 – 2.746 individuals/m2 with the main dominant species of Neanthes caudata, Prionospio malmgreni, Paraprionospio pinnata, Trichochaeta carica, Maldane sarsi, Capitella capitata, Terebellides stroemi, Euditylia polymorpha, Grandidierella lignorum, Apseudes vietnamensis. The biodiversity index values during the monitoring characterized for aquatic environmental conditions of mesotrophic to polytrophic. Besides, species richness positively correlated with DO, total nitrogen, and total phosphorus. The results confirmed the advantage of using benthic macroinvertebrates and their indices for water quality assessment

    Climate Change through the Studies of Volcano Rocks and Blue Icebergs

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    The investigation, by advanced physical methods, allows us to identify the chemical composition of volcano stones propelled from the deepness of the globe in various countries on the world and the blue icebergs detached from secular glaciers of Antarctic and Arctic poles. The stones and ashes of Island contain more elements than those of other volcanos, especially compared to those of Mediteranean countries. This confirms that the earthquake is much important and deeper under eastern Atlantic. Similarly, Sumatra volcano eruptions indicate pronounced tectonics under Western Pacific ocean. As a primary consequence, the planet temperature increases and induced the melting of thousands years glaciers at the North and South poles, rejecting in the oceans blue icebergs as big as Portugal or Vietnam. Nevertheless the sea level rising is not a great danger compared to its local sudden elevations, tsunamis, which cause tremendous damages. I have calculated the areas immerged by tsunamis, applied in particular for the deltas of North and South Vietnam, Indonesia; Malaysia and some European countries. The results will be presented in hope to prevent sudden damages and in long term, the effects on lands, environments and on the health of humanit

    DEVELOPMENT AND APPLICATION OF THE ENVIRONMENTAL HYDRODYNAMIC 3D MODEL FOR COMPUTATION AND FORECASTING OF OIL POLLUTIONS IN COASTAL MARINE ENVIRONMENT

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    Joint Research on Environmental Science and Technology for the Eart

    Development of PSO for tracking Maximum Power Point of Photovoltaic Systems

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    For a photovoltaic system, the relationship of the output voltage and power is usually non-linear, so it is essential to equip a MPPT controller in PV systems. Furthermore, the hotspot problem is a common phenomenon, resulting from the PV system operating under PSC. Partial shading not only damages the PV cells, but also makes it difficult to find the global MPP in the characteristic curves of P-V. The paper proposes a novel version of PSO, namely PPSO in order to detect the global peak among the multiple peaks, known as the true maximum energy from PV panel. For this, the PPSO algorithm makes the velocity of each particle be perturbed once the particles are struck into a local minima state in order to find the best optimum solution in the MPPT problem. The perturbation in the velocity vector of each particle not only helps them tracking the MPP accurately under the changing environmental conditions, such as large fluctuations of insolation and temperature like PSC; but also removes the steady-state oscillation. The proposed approach has been tested on a MPPT system, which controls a dc-dc boost converter connected in series with a resistive load. Moreover, the obtained results are compared to those obtained without any MPPT controller to prove the efficiency of the suggested method. In addition, this novel version gives the highest accuracy of tracking the optimum power in the least iteration number as compared to the conventional PSO

    Vietnam’s Accession to the World Trade Organization: Economic Projections to 2020

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    This study presents a set of assessments of the long term economic effects of Vietnam’s accession to the WTO. Generally speaking, our results indicate that Vietnam would benefit from accelerating its participation in more open multilateralism. However, it is also clear from our analysis that these benefits will remain modest in the absence of comprehensive and complementary domestic economic reforms. Passive external liberalization, even when coupled with determined domestic reform, is inferior to WTO participation combined with negotiated market access and other activist multilateral agreements. Finally, our analysis shows that capital insufficiency is a very serious constraint on Vietnamese economic growth and diversification. Capital market reform can play an essential role in dynamic and sustained economic development for the country.Vietnam, WTO, Trade

    DNA barcoding for identification of some fish species (Carangidae) in Vietnam coastal area

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    Carangidae family has got about 148 species belonging to 32 genera. In Vietnam, Carangidae is of high commercial value and playing an important role in the ecosystem. In the context Vietnam has received yellow card for seafood since Nov. 2017 by the EU, in which one of the main reasons was related to the restriction of traceability. In this study, DNA barcoding technique of mitochondrial cytochrome oxidase I (COI) gene was used to classify 56 specimens of Carangidae from three coastal areas (Northern, Central and Southern) in Vietnam to evaluate the effectiveness compared to the morphological classification method. Results showed that 21 species belonging to 16 genera were determined by the COI barcode while 18 species (16 genera) were determined when using morphological method. Seriola quinqueradiata and Trachinotus anak were newly recorded in Vietnam. From 56 sequences with 660 bp of mtDNA (COI), total 27 haplotypes were detected; haplotype diversity (h) and nucleotide diversity (π) were 0.903 ± 0.00060 and 0.14%, respectively. The DNA barcodes of COI gene of 21 species in Carangidae which were developed in this study could be used as a basis for comparison and traceability of their products. In addition, the results showed the high potentiality in using COI barcode to identify Carangidae fish in Vietnam

    Theoretical basis for reasonable population distribution in Tho Chu archipelago

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    Tho Chu archipelago is one of administrative units of Kien Giang province, Hon Nhan- one of its islands - is selected to become A1 base point of baseline for Vietnam territorial waters. If Tho Chau district is established, it will contribute to identifying sovereignty of Vietnam Southwest sea area following the United Nations Convention on the Law of the Sea, creating favourable conditions for islands’ socio-economic development, developing culture, enhancing effects of administration work and life quality of population in this island, firmly protecting sea border, securing island and sea sovereignty… However, the establishment of Tho Chu district appears in the context of streamlining administrative apparatus and limitation of capital for infrastructure construction in district level. This article focuses on the analysis of some factors affecting a reasonable population distribution in order to meet the requirement of building the Tho Chu into a district-level administrative unit in Kien Giang province

    A model of mother tongue-based bilingual education in Vietnam: Achievements and lessons learnt

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    This articlesummarizes findings from the implementation of the mother tongue-based bilingual education model and the tracer study on the students who participated in the mother tongue-based bilingual education program at preschool and primary schools and transitioned to higher levels of education in the framework of the UNICEFfunded "Learning for children" project. The research team would like to thank UNICEF Viet Nam,the Vietnam National Institute of Educational Sciences, Departments of Education and Training of Lao Cai, Gia Lai and Tra Vinh provinces, and educational managers, teachers and students in the three provinces for their support and cooperation.Education practices in ethnic minority areas in Vietnam with regional and ethnic differences influence its educational development. In particular, the language difference is a factor because the language used in teaching and learning is Vietnamese, not the mother tongue. Therefore, the mother tonguebased bilingual education model was developed to provide quick and convenient access to Vietnamese (the nation’s official language) and knowledge for students in ethnic minority areas. Its approach is to use the ethnic students’ mother tongues as the initial foundation in their first schooling years. The outstanding results of the successfully tested model have contributed to the improvement of the quality of ethnic minority education in Vietnam
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