188 research outputs found
Towards a Network of Marine Protected Areas in the South China Sea: Legal and Political Perspectives
The once pristine and rich marine environment of the South China Sea is degrading at an alarming rate due to the rapid socioeconomic development of the region. Despite this, and because mainly of complicated sovereignty and maritime boundary disputes, coastal States have not been able to develop effective regional cooperation to safeguard the shared marine environment. This dissertation, “Towards a Network of Marine Protected Areas in the South China Sea: Legal and Political Perspectives”, researches legal and political measures to support the development of a network of marine protected areas in the South China Sea. Such a network, if properly developed, would not only help to protect the marine environment and resources of the region but also contribute to lower the tension among its coastal States. These measures should be developed in accordance with international law, based on the specific geopolitical context of the South China Sea region and take into consideration experiences in developing regional networks of marine protected areas from other marine regions. Consequently, three optional categories of measures for the development of a network of marine protected areas in the South China Sea are suggested at the end. They include national-focused measures; measures to enhance the regional cooperation; and measures to build a regime for marine protected areas and network of marine protected areas in the South China Sea. These measures could be taken alternatively or on a step-by-step basis
Numerical solution of the problems for plates on some complex partial internal supports
In the recent works, Dang and Truong proposed an iterative method for solving some problems of plates on one, two and three line partial internal supports (LPISs), and a cross internal support. In nature they are problems with strongly mixed boundary conditions for biharmonic equation. For this reason the method combines a domain decomposition technique with the reduction of the order of the equation from four to two. In this study, the method is developed for plates on internal supports of more complex configurations. Namely, we examine the cases of symmetric rectangular and H-shape supports, where the computational domain after reducing to the first quadrant of the plate is divided into three subdomains. Also, we consider the case of asymmetric rectangular support where the computational domain needs to be divided into 9 subdomains. The problems under consideration are reduced to sequences of weak mixed boundary value problems for the Poisson equation, which are solved by difference method. The performed numerical experiments show the effectiveness of the iterative method
What explains Vietnam's exceptional performance in education relative to other countries? Analysis of the 2012, 2015, and 2018 PISA Data
Despite being the poorest or second poorest participant, Vietnam outperformed all other developing countries, and many wealthier countries, on the 2012, 2015, and 2018 PISA assessments. We investigate Vietnam's strong performance, evaluating several possible explanations for this apparent exemplary achievement. After correcting for potentially non-representative PISA samples, including bias from Vietnam's large out-of-school population, Vietnam remains a large positive outlier conditional on its income. Possible higher motivation of, and coaching given to, Vietnamese students can at most only partly explain Vietnam's performance. The child-, household- and school-level variables in the PISA data explain little of Vietnam's strong PISA performance relative to its income level. At most, they explain about 30% of Vietnam's exceptional performance in math and reading. Further research is needed to understand the exceptional performance of Vietnamese students
Environmental Issues in the South China Sea: Legal Obligation and Cooperation Drivers
Recently, we have been witnessing a critical level of a the degradation of the marine environment and depletion of fish stocks in the South China Sea. This has many adverse consequences on the politics, economics of the countries in the region as well as on the socio-economic life of the coastal population. One of the activities that has been causing serious damage to the marine environment and living resources of the South China Sea is the large-scale land reclamation and artificial island construction undertaken by China in the Spratly and Paracel islands recently. These activities have caused severe harm to the precious coral reef environment and thus, violated the obligation to preserve and protect fragile ecosystems and the habitat of depleted, threatened or endangered species under the international law of the seaThe paper explores the impact of China’s large-scale land reclamation and artificial island construction activities on the marine biodiversity of the South China Sea, explains what the legal obligation under the international law of States to protect and preserve the marine environment is and suggests a number of options in order to bring a halt to such activities and restore the damaged marine ecosystem. The paper puts particular emphasis on the cooperation drivers torwards a healthy, prosperous and peaceful South China Sea, which also contribute to the management and possibly, resolution of the current disputes in this region.Keywords: marine environmental issues, legal obligation, cooperation drivers, large-scale reclamation, artificial islands, blue solutions and fragile ecosystems
Effect of deposition time on gold nanodendrite porous structure and on signals of Hg(II) in environment
The influences of deposition time (tdep) for Au nanodendrite preparation on carbon cloth electrodes on the surface structure, electrochemical behavior and voltammetric signal for Hg(II) detection have been studied. The obtained results showed that from 60 s to 300 s, the longer deposition time, the larger dendrite length as well as the more increased density of dendrite structure became. Calculated from data showed that the electroactive surface area approached to the maximum value of 3.686 cm2 with tdep = 300 s. The typical electrochemical behaviour of the prepared electrodes was mass transfer diffusion to the electrode surface and being considered as planar diffusion. Using DPASV technique, the peak height of Hg(II) could appoach to 52 µA with tdep = 60 s. Keywords. Gold nanodendrite, deposition time, surface structure, electrochemical properties, mercury
MỘT SỐ KẾT QUẢ NGHIÊN CỨU BƯỚC ĐẦU VỀ ĐỘNG LỰC TRẦM TÍCH LƠ LỬNG TRONG MÙA LŨ TẠI VÙNG BIỂN VEN BỜ CỬA SÔNG HẬU
Land-ocean interactions in the coastal zone are severely influenced by tidal processces. In regions of high sediment discharge like the coast of Hau river estuary, these processes are even more significant when we analyse data in flood season (September) - which belongs to Agreement of Cooperation in Science and Technology between Vietnam and US (2013-2015) and project VAST-DLT.06/15-16 (2015-2016). Our goal is to investigate the sedimentation processes. Additionally, we investigated the influence of the tidal currents in relation to the suspended sediment. Salinity (PSU - Practical salinity unit), suspended sediment concentration (NTU - Nephelometric Turbidity Units) were measured by Compac-CTD (Depth temperature conductivity chlorophyll turbidity) and OBS-3A (Turbidity and Temperature Monitoring System) instruments. The results show that the suspended sediment concentration (SSC) correlate with tidal current velocities. The tidal current velocities are up to 60 cm/s near the surface and 40 cm/s near the bottom, increasing SSC in the water column at bottom layer (24 NTU) and decreasing SSC at surface layer (8 NTU). Processes of sediment transport and deposition in flood tide in flood season are influenced by tidal currents more significantly than those in dry season. This leads to an asymmetry of the tidal ellipses and the different deposition between seasons. The analytical results imply the influence of tide and tidal currents on SSC in the coast of Hau river estuary, hence, the spread, sea water and fresh water mixing processes have difference during tidal phases and seasons.Các mối tương tác biển - đất liền trong vùng ven bờ bị chi phối chủ yếu bởi các quá trình thủy động lực như sóng, dòng chảy, lưu lượng nước sông, thủy triều trong đó thủy triều đóng vai trò quan trọng. Tại các khu vực có lưu lượng phù sa lớn như vùng ven biển sông Hậu, các quá trình này càng trở nên rõ rệt khi phân tích từ số liệu khảo sát trong thời kỳ mùa lũ (tháng 9) thuộc chương trình hợp tác khoa học và công nghệ giữa Việt Nam và Hoa Kỳ (2013 - 2015) và đề tài độc lập mã số VAST-ĐLT.06/15-16 (2015 - 2016). Trong chuyến khảo sát này, mục đích là điều tra sự lắng đọng và phân bố theo không gian, thời gian của hàm lượng trầm tích lơ lửng. Ngoài ra, chúng tôi còn khảo sát ảnh hưởng của dòng triều trong mối tương quan với hàm lượng trầm tích lơ lửng. Độ muối (đơn vị PSU - Practical Salinity Unit), hàm lượng trầm tích lơ lửng (đơn vị đo NTU - Nephelometric Turbidity Units) được đo bằng thiết bị Compac-CTD (Depth temperature conductivity chlorophyll turbidity), và thiết bị đo độ đục OBS-3A (Turbidity and Temperature Monitoring System). Kết quả nghiên cứu cho thấy hàm lượng trầm tích lơ lửng tương quan với vận tốc dòng chảy. Tốc độ dòng chảy khi triều lên đến 60 cm/s ở lớp mặt và 40 cm/s ở đáy tạo nên sự tăng nồng độ trầm tích lơ lửng trong cột nước ở tầng đáy 24 NTU và 8 NTU tại tầng mặt. Trong pha triều lên, quá trình vận chuyển và lắng đọng trầm tích lơ lửng bị chi phối bởi dòng triều dài hơn so với mùa khô. Điều này cho thấy sự bất đối xứng của elip thủy triều và dẫn đến sự lắng đọng trầm tích lơ lửng trong các mùa là khác nhau. Từ kết quả phân tích có thể thấy vùng biển ven bờ cửa sông Hậu, hàm lượng trầm tích lơ lửng chịu sự chi phối bởi dòng chảy triều và thủy triều là rất lớn, do đó quá trình lan truyền, xáo trộn nước sông và biển có sự khác biệt đáng kể trong các điều kiện triều và điều kiện mùa
Study of Melting Temperature of Metals: Pressure Dependence
The melting temperature of metals are studied using the statistical moment method, going the quasi-harmonic appromations. The melting temperature of metals are calculated as a function of the pressure. We discuss the pressure dependence of melting temperatures of Ce, Fe metals and compare the present results with those of the experimental results
Study of CYP3A5 genetic polymorphism in Vietnamese Kinh ethnic group
Cytochrome P450 3A5 (CYP) belongs to the CYP3A cluster, which encode for several enzymes involved in metabolism of various drugs, endogenous substrates as well as exogenous compounds. Among the four genes of CY3A cluster, CYP3A5 plays an important role in pharmacogenetics since this enzyme metabolizes over 30% of the clinically prescribed drugs. The inter-individual variability in clearance of CYP3A substrates mainly depends on the genetic factors. In the present study, after collecting peripheral bloods samples from 100 unrelated healthy Kinh ethnic group in Vietnam, Sanger sequencing was used in order to determine the CYP3A5 variants responsible for enzyme activity alteration (*3, *6, *8 and *9). It was shown that CYP3A5*3 is the most prevalent variant with 67.5%, in which a haft of individuals carrying *3 were homozygous for this allele. In contrast, the variants *6, *8 and *9 were not found the study subjects. The data observed in current study would support dosing of drugs that metabolized by CYP3A5 and thereby increase treatment outcome.
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