91 research outputs found

    Identification and estimation of the marine ecosystem services surrounding selected offshore islands of Vietnam

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    Intertidal and larger marine ecosystems surrounding the islands of Bach Long Vi (Northern Vietnam), Con Co (Central Vietnam) and Tho Chu (Southernmost Vietnam) which have typical and valuable ecosystems are planned as marine protected areas. They are the study area of this paper on identification and estimation of these ecosystem services. The total economic valuation concept is used to estimate the total value of the ecosystems during the period March 2014 to October 2015. The marine ecosystems surrounding Bach Long Vi Island were estimated servicing 599,047.8 million VND (Vietnam Dong)/year in total (corresponding to 26.62 million USD (US dollar—1 USD = 22,503.68 VND (rate May 1, 2015)); calculated per hectare; this value corresponds with 94 million VND/year. The marine ecosystems surrounding Con Co Island provide a total monetary service of 267,518 million VND/year (approximately, 12 million USD/year); this corresponds with 307 million VND/ha/year. The marine ecosystems surrounding the Tho Chu archipelago were worth 565,236 million VND/year (approximately, 25 million USD/year); this corresponded with 125.47 million VND/ha/year. These figures show the most significant service value of marine ecosystems, particularly around the three islands

    In vitro antioxidant activity and bioactive compounds from Calocybe indica

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    Nowadays, the use of mushrooms in medicine is ubiquitous and has achieved particular success. The antioxidants in mushrooms can deactivate free radicals. This study assesses the antioxidant potential of mushroom Calocybe indica with the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging methods and the total antioxidant capacity. The mushroom’s ethanol extract exhibits acceptable activity with a low IC50 value (240.11 μg/mL), approximately 2.9 times lower than that of the mushroom Ophiocordyceps sobolifera extract. The ABTS scavenging rate of the extract is around 60% at 500 µg/mL, and the total antioxidant capacity is equivalent to 64.94 ± 1.03 mg of GA/g or 77.42 ± 0.42 μmol of AS/g.  The total phenolics, flavonoids, polysaccharides, and triterpenoids are equivalent to 29.33 ± 0.16 mg of GAE/g, 17.84 ± 0.11 mg of QUE/g (5.04 ± 0.04%), and 4.96 ± 0.04 mg of oleanolic acid/g, respectively. Specifically, the total triterpenoid content has been reported for the first time. The mushroom can have potential biomedical applications

    LƯỢNG GIÁ KINH TẾ GIÁ TRỊ DU LỊCH TỪ CÁC HỆ SINH THÁI BIỂN VÙNG ĐẢO BẠCH LONG VĨ, HẢI PHÒNG

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    Bach Long Vi island is an offshore district in the centre of the Gulf of Tonkin in Vietnam and administratively belongs to Hai Phong city. The island surrounded by abundant marine ecosystems with high biodiversity is one of 16 marine protected areas approved by the Prime Minister of Vietnam on 26/5/2010 according to the Decision No.742/QD-TTg. Currently, in addition to the main service of economic activities as fishery logistics, Bach Long Vi island still remains the wild features with beautiful scenery, fresh air and the diversity of marine species that are suitable for the development of eco-tourism and resorts. Although tourism at present is not developed yet, its potentials are promising. Deploying zone travel cost method (ZTCM), tourism potentials based on ecosystem services of Bach Long Vi island were estimated at 5.4 billion VND (Vietnamese currency). The value can be much higher if the infrastructure of the island is improved and the island is accessible more easily. Tourism potential valuation and identification of the advantages of the island strongly support tourism planning in the future.Đảo Bạch Long Vĩ là đảo xa bờ nhất của Việt Nam trong vịnh Bắc Bộ và về mặt hành chính là một huyện đảo trực thuộc thành phố Hải Phòng. Đảo có hệ sinh thái biển bao quanh khá phong phú, đa dạng sinh học cao, là một trong số 16 khu bảo tồn thiên nhiên biển Việt Nam đã được Thủ tướng chính phủ phê duyệt lựa chọn vào ngày 26/5/2010 theo Quyết định số 742/QĐ-TTg. Hiện nay, ngoài hoạt động kinh tế dịch vụ chính là hậu cần nghề cá, huyện đảo Bạch Long Vĩ vẫn giữ nguyên được nét hoang sơ với cảnh quan đẹp, không khí trong lành và sự đa dạng của các loài hải sản thích hợp với phát triển du lịch sinh thái, nghỉ dưỡng. Mặc dù hiện tại du lịch chưa phát triển ở vùng đảo, tuy nhiên tiềm năng du lịch rất lớn. Bằng phương pháp tính chi phí du lịch theo vùng (ZTCM), giá trị tiềm năng du lịch trên nền tảng các dịch vụ hệ sinh thái của đảo Bạch Long Vĩ được ước tính là 5,4 tỷ đồng/năm. Giá trị này còn cao hơn nhiều nếu hạ tầng cơ sở của đảo và khả năng đi lại thuận tiện. Ước tính giá trị tiềm năng du lịch và xác định cụ thể những yếu tố thuận lợi giúp khu vực này phát triển tốt du lịch trong tương lai

    FPGA-Based Multiple DDoS Countermeasure Mechanisms System Using Partial Dynamic Reconfiguration

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    In this paper, we propose a novel FPGA-based high-speed DDoS countermeasure system that can flexibly adapt to DDoS attacks while still maintaining system performance. The system includes a packet decoder module and multiple DDoS countermeasure mechanisms. We apply dynamic partial reconfiguration technique in this system so that the countermeasure mechanisms can be flexibly changed or updated on-the-fly. The proposed system architecture separates DDoS protection modules (which implement DDoS countermeasure techniques) from the packet decoder module. By using this approach, one DDoS protection module can be reconfigured without interfering with other modules. The proposed system is implemented on a NetFPGA 10G board. The synthesis results show that the system can work at up to 116.782 MHz while utilizing up to 39.9% Registers and 49.85% BlockRAM of the Xilinx Virtex xcv5tx240t FPGA device on the NetFPGA 10G board. The system achieves the detection rate of 100% with the false negative rate at 0% and false positive rate closed to 0.16%. The prototype system achieves packet decoding throughput at 9.869 Gbps in half-duplex mode and 19.738 Gbps in full-duplex mode

    Vietnam geographical exploitation under the United Nations Convention on the Law of the Sea in 1982 (UNCLOS 1982)

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    As an active member of the United Nations Convention on the Law of the Sea - UNCLOS, Vietnam has completed 3 Reports on the Limits of the Continental Shelf and has submitted two of them to the Commission on the Limits of the Continental Shelf - CLCS, before the deadline 13-5-2009. Those are: (1) Outer Limits of the Vietnam’s Extended Continental Shelf: North Area (VNM-N); (2) Outer Limits of the Vietnam’s Extended Continental Shelf: Middle Area (VNM-M) and (3) Vietnam - Malaysia Joint Continental Shelf Submission. The VNM-M has not yet been submitted but it was mentioned to the CLCS and will be submitted in the appropriate time.Vietnam’s submissions were highly appreciated by CLCS; although the CLCS has not yet organized a special sub-committee to look at our reports, the secretariat of CLCS has already posted the executive reports of our submissions, with our principle claims on the continental shelf, on the website of the CLCS since May 2009. This paper presents shortly the UNCLOS and its application in Vietnam case

    A Phase 2/3 double blinded, randomized, placebo-controlled study in healthy adult participants in Vietnam to examine the safety and immunogenicity of an inactivated whole virion, alum adjuvanted, A(H5N1) influenza vaccine (IVACFLU-A/H5N1)

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    Abstract Background A global shortfall of vaccines for avian influenza A(H5N1) would occur, especially in low- and-middle income countries, if a pandemic were to occur. To address this issue, development of a pre-pandemic influenza vaccine was initiated in 2012, leveraging a recently established influenza vaccine manufacturing capacity in Vietnam. Methods This was a Phase 2/3, double-blinded, randomized, placebo-controlled study to test the safety and immunogenicity of IVACFLU-A/H5N1 vaccine in healthy adults. Phase 2 was a dose selection study, in which 300 participants were randomized to one of the three groups (15 mcg, 30 mcg, or placebo). Safety and immunogenicity were assessed in all participants. In Phase 3, 630 participants were randomized to receive the IVACFLU-A/H5N1 vaccine dose selected in Phase 2 (15 mcg, n = 525) or placebo (n = 105). Safety was assessed in all Phase 3 participants and immunogenicity was measured in a subset of participants. Results The vaccine was well tolerated and most of the adverse events were mild and of short duration. Mild pain at the injection site was the most common adverse event seen in 60 percent of participants in the vaccine group in Phase 3. In Phase 2, both 15 mcg and 30 mcg doses were immunogenic, so the lower dose was selected for further testing in Phase 3. In Phase 3 overall seroconversion rates were 68 percent for hemagglutination inhibition (HI), 51 percent for microneutralization (MN) and 56 percent for single radial hemolysis (SRH). The seroprotection rates were 44 percent for HI, 41 percent for MN and 55 percent for SRH. The GMT ratio was 5.31 and 3.7 for HI and MN respectively; GMA was 4.75 for the SRH. Conclusion The IVACFLU A/H5N1 was safe and immunogenic. Development of this pandemic avian influenza vaccine is a welcome addition to the limited global pool of these vaccines. ClinicalTrials.gov register NCT02612909

    Potential application of rhizobacteria isolated from the Central Highland of Vietnam as an effective biocontrol agent of robusta coffee nematodes and as a bio-fertilizer

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    [[abstract]]Robusta coffee is a major commercial crop in the Central Highland of Vietnam with high economic and export value. However, this crop is adversely affected by various pathogens, particularly nematodes. This study aimed to screen active anti-nematode rhizobacterial strains for sustainable coffee production. Among more than 200 isolates, the isolate TUN03 demonstrated efficient biocontrol with nearly 100% mortality of J2 coffee nematodes Meloidogyne spp. and 84% inhibition of nematode egg hatching. This active strain was identified as Pseudomonas aeruginosa TUN03 based on its 16S rRNA gene sequence and phylogenetic analysis. In greenhouse tests, the strain TUN03 significantly reduced the coffee nematode population in the rhizome-soil with an 83.23% inhibition rate and showed plant growth-promoting effects. Notably, this is the first report of the nematicidal effect of P. aeruginosa against coffee nematodes. This potent strain further showed an antifungal effect against various crop-pathogenic fungi and was found to be the most effective against Fusarium solani F04 (isolated from coffee roots) with a 70.51% inhibition rate. In addition, high-performance liquid chromatography analysis revealed that this bacterial strain also secretes plant growth regulators including indole acetic acid (IAA), gibberellic acid (GA3), kinetin, and zeatin in significant amounts of 100, 2700, 37, and 9.5 µg/mL, respectively. The data from this study suggest that P. aeruginosa TUN03 may be a potential biocontrol agent and biofertilizer for the sustainable production of Robusta coffee and other crops.[[sponsorship]]科技部[[notice]]補正完

    Interactions between climate change, urban infrastructure and mobility are driving dengue emergence in Vietnam.

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    Dengue is expanding globally, but how dengue emergence is shaped locally by interactions between climatic and socio-environmental factors is not well understood. Here, we investigate the drivers of dengue incidence and emergence in Vietnam, through analysing 23 years of district-level case data spanning a period of significant socioeconomic change (1998-2020). We show that urban infrastructure factors (sanitation, water supply, long-term urban growth) predict local spatial patterns of dengue incidence, while human mobility is a more influential driver in subtropical northern regions than the endemic south. Temperature is the dominant factor shaping dengue's distribution and dynamics, and using long-term reanalysis temperature data we show that warming since 1950 has expanded transmission risk throughout Vietnam, and most strongly in current dengue emergence hotspots (e.g., southern central regions, Ha Noi). In contrast, effects of hydrometeorology are complex, multi-scalar and dependent on local context: risk increases under either short-term precipitation excess or long-term drought, but improvements in water supply mitigate drought-associated risks except under extreme conditions. Our findings challenge the assumption that dengue is an urban disease, instead suggesting that incidence peaks in transitional landscapes with intermediate infrastructure provision, and provide evidence that interactions between recent climate change and mobility are contributing to dengue's expansion throughout Vietnam
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