136 research outputs found

    A methodology for validation of integrated systems models with an application to coastal-zone management in South-West Sulawesi

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    Integrated Systems Models (ISMs) have been developed over decades to support the planning and management of natural resources and the environment. The development of these models is based on the concepts of systems approach and integrated approach. However, the lack of a generally accepted definition of model validity and model validation, the inherent complexity of ISMs, the poor predictive value of historical data related to the natural-human system, the scarcity of field data and the high level of aggregation of ISMs make the validation of ISMs an extremely difficult task (Chapter 1). These problems raise a number of important questions, such as: to what extent can such models contribute to our knowledge and ability to manage the environment? Do they have added value in comparison with conventional process models? Centred in these questions are the two questions: how can the validity of an ISM be defined? How can this validity be determined? This thesis is aimed at answering these two questions

    Reproductive biology of the mudskipper Boleophthalmus boddarti in Soc Trang

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    The mudskipper Boleophthalmus boddarti is an amphibious fish widely distributed in the mudflat regions in Asia, but its reproductive biology was poorly stydied. This study was conducted in the Tran De, Soc Trang, Vietnam, from March 2013 to February 2014, to investigate reproductive parameters of B. boddarti. Data analysis based on a total of 360 collected fish (188 females and 172 males) suggest that the sex ratio of this mudskipper was not significantly different between dry and wet seasons. This fish was a multiple reproducer and spawned in the wet season with a peak spawning in three main months of this season (August to October) as difference stages of oocytes were observed in the ovaries. The male B. boddarti released sperms during the reproductive season since different type of spermatogonia were found in stage V testis sections. This fish reached 11.52 cm total length at first sex maturation and was high fecundity (9,800-33,800 eggs), indicating a possible adaptation of this species to the monsoonal climate. The understanding of the reproductive biology of B. boddarti provides useful knowledge of its reproductive adaptation to the mudflat toward sustainable management in the study region

    Investigation of anti-inflammatory lignans from the leaves of Symplocos sumuntia Buch-Ham ex D Don (Symplocaceae)

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    Purpose: To investigate the anti-inflammatory activity of Symplocos sumuntia Buch.-Ham. ex D. Don and identify the main secondary metabolites responsible for this effect.Methods: The in vitro anti-inflammatory activity of the plant extract and isolated compounds was determined in terms of the ability to inhibit the production of nitric oxide (NO), and expressions of iNOS and COX-2 proteins in RAW264.7 cells stimulated by lipopolysaccharide (LPS). Compounds were isolated and identified by spectroscopic methods.Results: The methanol extract of S. sumuntia leaves showed strong inhibitory effects on nitric oxide (NO) production and expression of iNOS and COX-2 in LPS-induced RAW264.7 cells. A phytochemical assay-guided fractionation of the methanol extract of S. sumuntia leaves led to the isolation of four lignans which are arctigenin (1), matairesinol (2), monomethylpinoresinol (3) and pinoresinol (4). These compounds were identified for the first time from S. sumuntia. All four compounds inhibited the production of nitric oxide (NO), with arctigenin showing the most potent activity with half-maximal inhibitory concentration (IC50) value of 4.08 μM.Conclusion: S. sumuntia is a promising source of anti-inflammatory agents, which may clarify to the therapeutic use of this plant in Vietamese traditional medicine.Keywords: Symplocos sumuntia, Symplocos caudata, Lignan, Arctigenin, Anti-inflammator

    Extracting Conditions Optimization and Bioactivity of Polysaccharides from the Pods of Haricot Vert

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    Polysaccharides from the pods of haricot vert (Phaseolus vulgaris L.) were extracted using a simple heating method, by varying extracting temperature, heating time, solid-to-liquid ratio, and solvent compositions. The obtained results were processed using statistical analysis that helped to identify the optimal conditions for the polysaccharides’ extraction process. This study represents a promising production method of bioactive polysaccharides extract in the food and pharmaceutical industry

    Isogeometric Analysis for BIM-Based Design and Simulation of Sub-Rectangular Tunnel

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    The design and analysis of segmental tunnel lining is today often based on empirical solutions with simplified assumptions. This work showcases the application of Isogeometric Analysis (IGA) for computationally efficient simulations of tunnel linings [1, 2]. In our past research, we developed a design-through-analysis procedure that consists of i) parametric modeling of the segmented tunnel lining; ii) development of an IGA computational framework, iii) reconstruction of the BIM lining model for IGA analysis, and iv) simulation model for lining including a reconstructed IGA model, contact interfaces between the joints, and a non-linear soil-structure interaction model based on the Variational Hyperstatic Reaction Method (VHRM) [3].In this paper, we extend our method for the analysis of subrectangular tunnel linings and demonstrate its efficiency using the example of the Shanghai express tunnel. The advantage of our novel method is the flexibility in adapting the tunnel alignment with the help of NURBS/CAD technology. Employing the high-order geometry definition, convergence of the mesh refinement procedure can be obtained with much faster rate. As a result, the modelling effort and computational time are reduced significantly. Moreover, this approach allows to capture the bending moment with better regularity. The combination with an existing BIM modelling approach via geometryreconstruction leads to a very efficient framework for tunnel lining analysis and design

    Investment in human capital and labor productivity in Vietnam : the case study on small and medium enterprises

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    This paper investigates the importance of training in Small and Medium Enterprises (SMEs) in Vietnam as a basis for improving productivity. Current training courses are ineffective, and need to be associated with practical work. Trainers need appropriate experience as well as knowledge of how to organize classes. SME Support Centres are evaluated in terms of trainers and training: findings show that training organization for SMEs should be classified by types of trainees; courses for employees should focus on particular skills; and policies should encourage management skills training as well. Development of new curriculum materials is urgent

    Consequences of infertility in developing countries: results of a questionnaire and interview survey in the South of Vietnam

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    BACKGROUND: This study explores the psychological, socio-cultural and economic consequences of infertility on couples' life. The purpose of this research is to improve knowledge about the potentially serious implications of infertility in the South of Vietnam. METHODS: This study included 118 infertile couples who filled in questionnaires and 28 men and women who were interviewed. RESULTS: Data of the questionnaire show men and women do not differ in their responses and attitudes towards infertility. Almost one-third of the participants require psychological support. Interviewees experience secrecy, social pressure and economic hardship. CONCLUSION: Offspring are very important to Vietnamese couples. Their future depends on children. Family plays an important role in the experiences of the infertile couple. Economic consequences are a particular distressing factor. There is a need for psychological counselling in the treatment of infertile couples in the South of Vietnam. It should be realised that in developing countries, despite overpopulation, unwanted childlessness is an important social and economical burden that needs attention

    A community participatory intervention model to reduce the health risks from biogas wastewater in Hanam Province, Vietnam

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    In Vietnam, using biogas to treat livestock waste is common, in particular on small holder farms. However, most small holder farms do not know how to use biogas correctly and wastewater can affect health and the environment. Using a participatory approach with farmers and other stakeholders we developed and implemented a set of interventions in Hanam province to reduce health risks from biogas wastewater. Twenty-four pig farmers were selected as a "core group" to be instrumental in developing the interventions and training other farmers to correctly use biogas. The intervention model was piloted for 6 months. Several outputs were obtained including i) approval and enforcement of a "huong uoc - village law" on environmental protection; ii) training of 24 farmers from the core group in communication skills to share information on using biogas; iii) development of a 6-step program of pig cage cleaning to limit waste loaded to biogas to improve the efficiency of biogas production; iv) a health monitoring books for humans and animals for use by families in the community. The results provided evidence that applying the participatory approach can lead to improved knowledge and practices of farmer using biogas and can reduce the health risks from biogas wastewater

    Purification and characterization of novel fibrinolytic proteases as potential antithrombotic agents from earthworm Perionyx excavatus

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    Six protease fractions, namely FI, FII, FIII-1, FIII-2, FIII-3 and FIV, were isolated from Perionyx excavatus earthworm biomass by acetone precipitation, followed by serial chromatography using anion exchange, hydrophobic interaction and size exclusion chromatography. All fractions exhibited strong hydrolytic activity towards casein. The activity of six fractions towards fibrin, determined by fibrin plate assay, ranged from 44 to 831 plasmin unit.mg-1 and ranked as FIII-3 > FIII-2 > FI > FIII-1 > FIV > FII. Casein degradation was optimal at pH 7 and 11, and at 45-60°C. All fractions were considerably stable at high temperature and wide pH range. They were completely inhibited by phenylmethylsulfonyl fluoride (PMSF). The molecular weights (MW) and isoelectric points (pI) determined by 2D-electrophoresis were 27.5-34.5 kDa, and 4.3-5.2, respectively. Tandem mass spectrometry (MS) analysis was used to deduce the amino acid sequences of some peptides from FIII-1 and FIII-2. The sequences shared 16.9% and 13.2% similarity, respectively, with the fibrinolytic enzymes from two related earthworm species, Lumbricus rubellus and Eisenia fetida. The P. excavatus proteases were classified as serine proteases. They could perform rapid hydrolysis on both coagulated fibrous fibrin and soluble fibrinogen monomers without the presence of activators such as tPA or urokinase

    The fluidic molecular trajectory and the Nano-droplet production ability

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    This paper studies the liquid Nano-droplet production ability using molecular dynamics simulation methodology. The research parameter is performed at the temperature of 310 Kelvin (K), the pressing force of 10.0 × 10−10 Newton (N) and the ejective hole diameters of 25 and 40 Angstrom (Å). The research result shows that liquid Nano-droplets finally were not produced for the ejective diameter of 25 Å. The Nano-jets were not only non-destruction from nozzle’s surface to produce the droplets but also movement downward to come back the nozzle’s surface. The molecular trajectory is very zigzag and curved both inside and outside the ejective container. In the contrary, when increasing the ejective diameter to 40 Å, the liquid Nano-droplet was produced in the same the ejective time and compressible force magnitude. The molecular trajectory is quite straight after ejecting out the outside of the container. Meanwhile, for the nozzle diameter size of 40 Å, the Nano-droplet was not only production but also movement up to leave away the nozzle’s surface under same above conditions. That proves that the ejective diameter has the influences to the moveable direction and Nano-droplets formation ability in the whole ejective process
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