358 research outputs found

    Species list and conservation priority of butterflies (Lepidoptera, Rhopalocera) in Dong Van karst plateau, Ha Giang

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    Study species and conservation priority of butterflies in Dong Van Karst Plateau, Ha Giang province was carried out in forests of Lung Cu, Pho Bang, Ta Phin and sites near Dong Van centre. The habitats are the natural forest on mountain, the secondary forest, the forest edge, shrub and grass from 1,400 to 1,700 m a.s.l. The study was carried out sometimes from May to September from in 2008, 2010 and 2011. Total 132 species of 8 butterfly families were recorded during studied period. Two species listed in the Red Data Book of Vietnam and CITES are Troides aeacus and Teinopalpus imperialis. There are 33 species with individuals 1-2 (25% of all species), 44 species with individuals 3-5 (33% of all species), 14 species with individuals 6-10 (11% of all species), and 41 species with individuals more than 10 (31% of all species). Butterfly species of Dong Van karst plateau consists of 12.6% of all butterfly species of Vietnam, but the family Papilionidae of Dong Van karst plateau consists of 40% of all species of the family of Vietnam. The family Papilionidae is very important for conservation of insects. Some species distributed in Vietnam merely found in the studied area are Byasa hedistus, Papilio elwesi, Sasakia funeblis, S. charonda, and Melitaea yuenty. These species are rare and distribute in forests where forests are being declined. So it is needed conservation meseasures to conserve, especially conserve the natural forests in Dong Van karst plateau, the habitat of these butterflies

    Optimization of Logistics Services in Vietnam Through LOGIVAN Application

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    Logistics is a type of service that plays an important role in promoting the country's economic growth. In addition, it is also of great significance to the transport sector in Vietnam in dealing with the challenges of traffic congestion in large cities. In Vietnam today, logistics services are growing. However, there is one major limitation that still exists, that is freight costs are still high. This does not meet the best requirements of customers. There are many reasons for this problem, one of the reasons is that trucks only carry one-way cargo, but there are no goods to ship backwards. The paper studies the application of LOGIVAN smart transport model in developing Logistics services in Vietnam today. Research results show that LOGIVAN transport model is the optimal model in solving the problem of empty cars in the transport of goods when they go back to the place of departure. This helps minimize Logistics costs for businesses, increases income for drivers and leads towards sustainable transport development. LOGIVAN develops two platform solutions for goods owners and vehicle owners. Accordingly, the author of the article confirms the quality of this model in developing Logistics services in Vietnam and guide the operation for users via applications on personal mobile devices at the same time. Keywords: Logistics; LOGIVAN; Vietnam. DOI: 10.7176/JESD/10-14-01 Publication date:July 31st 202

    Warming threat compounds habitat degradation impacts on a tropical butterfly community in Vietnam

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    AbstractSpecies are threatened globally by multiple and often synergistic environmental changes including habitat loss, fragmentation and climate change. However, how these changes act in concert is poorly understood, especially in the tropics where the vast majority of biodiversity resides. Here, using a unique dataset covering 10~years of butterfly surveys (2003–2013) at Tam Dao National Park in northern Vietnam, we examined the combined impacts of habitat degradation (following intensive infrastructure development in 2005) and the possible threat of warming (extrapolating upon the relationship between natural climatic variation and community indices) for tropical butterfly communities. We found that both habitat degradation and warmer temperatures led to fewer narrow-range and forest-associated species comprising the sampled communities. Under projected climate change scenarios, the impact of warming was comparable to habitat degradation with respect to community change, and degraded forest communities were projected to shift towards cosmopolitan and non-forest species even more. The tropics have been heavily deforested world-wide and also suffer from heavy impacts of degradation and fragmentation, especially road construction. Warming will compound habitat degradation impacts such that the conservation of tropical biodiversity will require addressing these multiple global changes simultaneously

    Speed profile optimization of an electrified train in Cat Linh-Ha Dong metro line based on pontryagin's maximum principle

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    An urban railway is a complex technical system that consumes large amounts of energy, but this means of transportation still has been obtained more and more popularity in densely populated cities because of its features of high-capacity transportation capability, high speed, security, punctuality, lower emission, reduction of traffic congestion. The improved energy consumption and environment are two of the main objectives for future transportation. Electrified trains can meet these objectives by the recuperation and reuse of regenerative braking energy and by the energy - efficient operation. Two methods are to enhance energy efficiency: one is to improve technology (e.g., using energy storage system, reversible or active substations to recuperate regenerative braking energy, replacing traction electric motors  by energy-efficient traction system as permanent magnet electrical motors; train's mass reduction by lightweight material mass...); the other is to improve operational procedures (e.g. energy efficient driving including: eco-driving; speed profile optimization; Driving Advice System (DAS); Automatic Train Operation (ATO); traffic management optimization...). Among a lot of above solutions for saving energy, which one is suitable for current conditions of metro lines in Vietnam. The paper proposes the optimization method based on Pontryagin's Maximum Principle (PMP) to find the optimal speed profile for electrified train of Cat Linh-Ha Dong metro line, Vietnam in an effort to minimize the train operation energy consumption

    Using Malaise traps for collecting Lepidoptera (Insecta), with notes on the preparation of Macrolepidoptera from ethanol

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    The present paper deals with the potential of employing Malaise traps for collecting butterflies and moths for morphological analysis and presents a protocol for preparing Macrolepidoptera from Malaise trap samples that were preserved in ethanol. About 80 specimens of Lepidoptera, including Nymphalidae, Geometridae, Hesperiidae, Erebidae, Noctuidae, Pyralidae and Tortricidae, were mounted, following the protocol. All specimens with robust wings and contrasting wing patterns were well suited for the study of external morphology, regardless of the family. The specimens used in this study were collected in highland forest areas of central Vietnam with a little known entomofauna, as part of the German-Vietnamese biodiversity project 'VIETBIO'. The study offers new methodological approaches in an attempt to make the most of the material that was obtained using Malaise traps

    Incidence of dengue and chikungunya viruses in mosquitoes and human patients in border provinces of Vietnam

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    Background: Dengue virus remains a major threat in Vietnam, while chikungunya virus is expected to become one. Surveillance was conducted from 2012 to 2014 in Vietnam to assess the presence of dengue and chikungunya viruses in patients hospitalized with acute fever in five Vietnam provinces neighboring Lao PDR and Cambodia. Surveillance was extended to mosquitoes present in the vicinity of the patients' households. Results: A total 558 human serum samples were collected along with 1104 adult mosquitoes and 12,041 larvae from 2250 households. Dengue virus was found in 17 (3%) human serum samples and in 9 (0.8%) adult mosquitoes. Chikungunya virus was detected in 2 adult mosquitoes (0.18%) while no chikungunya virus was detected in humans. Differing densities of mosquito populations were found, with the highest in the Long An Province border with Cambodia. Long An Province also displayed the lowest rate of infection, despite a very high Breteau Index, high human population density and presence of the main cross border road system. The highest incidence was found in Dac Nong Province, where the Breteau and Container indices were the second lowest. Dengue virus was detected in five Aedes albopictus, three Aedes aegypti and one Culex vishnui. Chikungunya virus was detected in two Ae. aegypti. All infected mosquitoes belonged to haplotypes described in other parts of the world and a number of novel haplotypes were found among uninfected mosquitoes. Conclusions: Dengue is considered to be regularly introduced to Vietnam from Cambodia, mostly through human movement. The data reported here provides a complementary picture. Due to intensive international trade, long-distance transportation of mosquito populations may play a role in the regular importation of dengue in Vietnam through Ho Chi Minh City. It is important to decipher the movement of mosquitoes in Vietnam, not only at the Lao PDR and Cambodia borders but also through international trade routes. Mosquito surveillance programs should address and follow mosquito populations instead of mosquito species

    Phenolic compounds from leaves of Amensiodendron chinese (Sapindaceae)

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    From the ethyl acetate extract of the leaves of Amensiodendron chinense (Merr.) Hu (Sapindaceae), we isolated three known phenolic compounds: 4-hydroxy-3-methoxybenzaldehyde (1), methyl 3,4-dihydroxybenzoate (2), and 3,4-dihydroxybenzoic acid (3). We elucidated their chemical structures from the spectral data and compared them with those reported in the literature.3 hợp chất phenolic được phân lập từ cao chiết ethyl acetate của lá thuộc loài Amensiodendron chinese (Merr.) Hu (Sapindaceae) bao gồm : 4-hydroxy-3-methoxybenzaldehyde (1), methyl 3,4-dihydroxybenzoate (2), 3,4-dihydroxybenzoic acid (3). Cấu trúc hóa học được xác định dựa vào dữ liệu phổ và so sánh với tài liệu tham khảo

    Isolation and identification of indole acetic acid producing bacteria from the coasts of Ben Tre and Tra Vinh Provinces

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    Beneficial plant-growth-promoting bacteria (PGPB) have been reasonably applied to rescue crucial issue for agriculture by salinity soil. Observed most of PGPB was found in endophyte, rhizosphere and soil. Indole acetic acid (IAA)-producing bacteria could naturally stimulate and facilitate plant growth. The knowledge of IAA production and content of bacteria resident in the marine environment has been typically insufficient and limited to date. In recent years, unwarrantable intrusions of sea water have been enlarged in the Mekong River Delta of Vietnam, threatening productive rice fields, local fruits, and cash crops. Therefore, finding PGPB in the coastal regions in the Mekong River Delta as a creative resource for sustainable agriculture is necessary and is a prompt challenge. In this study, IAA-producing bacteria from coastal regions of Ben Tre and Tra Vinh Provinces were isolated and adequately identified. Out of 202 bacterial isolates, 10 isolates showed the possible ability to produce IAA from L-tryptophan. These 10 isolates were objectively evaluated the capacity to produce IAA under 5% (w/v) NaCl in King B and marine broths. The results revealed that IAA production decreased in 5% NaCl, even though bacterial growth increased. These 10 IAA-producing bacteria were classified at the species level, Marinobacter hydrocarbonoclasticus, M. pelagius, M. daepoensis, and Mameliella phaeodactyli by 16S rRNA gene analysis. The most IAA producer in King’s B broth, the isolate C7, was investigated in more detail. The isolate C7 produced the maximum IAA amount (192.2 ± 1.14 µg/ml) under the presence of 20 g/l yeast extract, 2 g/l of L-tryptophan and 1% NaCl. The isolate C7 was able to grow at 1–17% (w/v) NaCl (optimum, 4%), but not in the absence of NaCl, indicating it is a moderate halophilic bacteria. This study highlighted the considerable ability to produce IAA of marine bacteria, which could be thoughtfully considered to use naturally as biofertilizers to promote plant growth in saline intrusion lands.

    Synthesis and Optical Characterization of Dye Doped in Ormosil Nanospheres for Bioapplications

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    Dye-doped ORMOSIL (organically modified silicate) nanoparticles (NPs) have significant advantages over single-dye labeling in signal amplification, photostability and surface modification for various biological applications. The dyes: Rhodamine 6G (R6G) and Rhodamine B (RB) were successfully incorporated into ORMOSIL nanoparticles fabricated by micellar nanochemistry from Trimethoxysilane CH3_3Si(OCH3_3)3_3 precursor. The optical characterization of dye-doped ORMOSIL NPs was studied in comparison with it’s of free dye in solution. The results shown that the photostability of ORMOSIL dye doped nanospheres is much improved in comparison with it’s of dye in solution. Other studies of the photophysical properties such as anisotropy, fluorescence lifetime and energy transfer were also done
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