Vietnam Academy of Science and Technology: Journals Online
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Study and application of Symphonie model to compute the hydrodynamic processes in the East Sea
Get PDFHydrodynamic processes in the East Sea have been studied by many Vietnamese and foreign scientists applying the models as advanced tools with low cost and spatial and temporal synchronized dataset to serve their research. However, applying the model to study variability of small and medium structures with very high resolution (a few kilometers) is still challenge for scientists. With the advantages of high quality real-time data, open source hydrodynamic model, and the support from high performance computer (HPC) systems, we have step by step studied and developed the numerical model for study on hydrodynamic fields in the East Sea. The model was validated with high resolution satellite data as well as in-situ data from the ARGO and research vessels. Initial results of the simulation are very good for the surface seawater temperature (SST) field in the East Sea
Effects of dietary Mannan oligosaccharide (MOS) on grown, survival rate, intestinal morphology and blood cell count of the golden trevally fish (Gnathanodon specious)
Get PDFThe golden trevally fishes (Gnathanodon specious) (2.19 ± 0.23 g) were cultured in glass tanks with density of 20 fishes/tank and they were fed supplemental diets of different MOS concentrations (0; 0.2; 0.4 and 0.6%) for 90 days. Collected data included growth rate, survival rate and some hematological characteristics of this fish. The results demonstrated that MOS supplementation did not affect growth performance, erythrocyte density and blood cell size, however the survival rate was significantly increased. On the other hand, the total number of white blood cells (BC) on the 60th day in the fish fed with MOS supplements (5.78–6.96 × 104TB/mm3) was higher than that in the control group (only 5.43 × 104TB/mm3) with the largest total leukocytes (6.96 ± 0.50 × 104TB /mm3) at 0.2% MOS (p 0.05)
Quasi Three-parametric -matrix and Quantum Supergroups and
No full textAn overparametrized (three-parametric) R-matrix satisfying a graded Yang-Baxter equation is introduced. It turns out that such an overparametrization is very helpful. Indeed, this R-matrix with one of the parameters being auxiliary, thus, reducible to a two-parametric R-matrix, allows the construction of quantum supergroups GLp,q(1/1) and Up,q[gl(1/1)] which, respectively, are two-parametric deformations of the supergroup GL(1/1) and the universal enveloping algebra U[gl(1/1)]. These two-parametric quantum deformations GLpq(1/1) and Upq[gl(1/1)], to our knowledge, are constructed for the first time via the present approach. The quantum deformation Up,q[gl(1/1)] obtained here is a true two-parametric deformation of Drinfel’d-Jimbo’s type, unlike some other one obtained previously elsewhere
Erratum: Mott Transition in the Mass Imbalanced Ionic Hubbard Model at Half Filling
Get PDFErratum: Mott Transition in the Mass Imbalanced Ionic Hubbard Model at Half Filling[Nguyen Thi Hai Yen, Le Duc Anh, Hoang Anh Tuan, Nguyen Toan Thang and Tran Thi Thu Trang, Communications in Physics, Vol. 29, No. 3SI (2019), pp. 305-312]This paper was published on 22 October 2019 with an omission in the text of the author’s list. The author list should read asNGUYEN THI HAI YEN, LE DUC ANH, HOANG ANH TUAN, NGUYEN TOAN THANG, TRAN THI THU TRANG AND NGUYEN THI HUONGInstitute of Physics, Vietnam Academy of Science and Technology (VAST), Hanoi, Vietnam Hanoi National University of Education, Hanoi, Vietnam Graduate University of Science and Technology, VAST, Hanoi, Vietnam Ha Long University, Quang Ninh, Vietnam Thuy Loi University, Hanoi, VietnamE-mail: [email protected] author’s list has been corrected as of 29 November 2019. The author’s list has been corrected in the electronic version of the journal
Instrument Radiometric Processing for Earh Observation Satellite Optical Payload
No full textThe radiometric calibration procedure, applied on VNREDSat-1 raw data shall correct and minimize the radiometric non-uniform gain and offset, occurred by the nature of the optical payload. The procedure is based on the radiometric model, built to transform the incoming radiance into camera output signal. Within this radiometric model, the radiometric parameters such as dark noise and pixel response non-uniformity shall be separated. The output signal of dark noise shall be measured by capturing image scene of the ocean at night. The output signal of pixel response non-uniformity shall be measured by capturing image scene of uniform radiance image scene such as the dessert or grass field. All the radiometric calibration parameter after calculated shall be saved into a calibration file, which is kept on the control station and image processing station
OPTIMAL FERMENTATION CONDITIONS FOR ANTIBIOTIC PRODUCTION BY ENDOPHYTIC Streptomyces cavourensis YBQ59 ISOLATED FROM Cinnamomum cassia Presl
Get PDFThis study determined the optimal nutrient and environmental conditions for the production of antimicrobial and cytotoxic agents by Streptomyces cavourensis YBQ59 during the fermentation process. The antimicrobial and cytotoxic activities of eluted fractions based gradient solvents via silica gel column of chromatograph were also evaluated. S. cavourensis YBQ59 exhibited strong, board-spectrum antimicrobial activities under fermentation conditions as follows: MT6 medium with soluble starch and soybean powder as carbon and nitrogen sources, respectively, temperature 30oC, initial pH 7.0, 20% DO concentration and with 5% initial seed culture. The kinetic of fermentation showed that the antimicrobial and cytotoxic activities were highest at between 72h and 78h. The fraction 25/1 D-M (dichloromethane –methanol) exhibited the highest antimicrobial effect against methicillin-resistant Staphylococcus aureus ATCC 33591 and methicillin-resistant Staphylococcus epidermidis ATCC 35984 with minimum inhibitory concentrations of 9.4 µg/ml and 6.4 µg/ml, respectively. The fraction 10/1 D-M had strong cytotoxic effects towards multidrug-resistant A459 and H1299 lung carcinoma cell lines with the cell viability of 11.3% and 12.4%, respectively. In conclusion, S. cavourensis YBQ59 would be a potential producer of valuable bioactive compounds that may have a board application in pharmaceutical industry and agriculture (biocontrol, livestock, food safety and quality management
OPTIMIZATION OF CONDITIONS FOR CAROTENOIDS EXTRACTION FROM SHRIMP WASTE USING ORGANIC SOLVENT
Get PDFIn this study, factors affecting the extraction yield of carotenoids from dry shrimp waste by organic solvents such as ratio of hexane / acetone, ratio of solvent / shrimp waste, extraction temperature, extraction time, extraction method such as dynamic or static have been studied. The results showed that the solvent ratio hexane: acetone = 3: 1 gave the highest carotenoid yield. In this ratio of solvent’s mixture, the yield reached highest at temperature 60 °C for 2 hours, which was 44,64 µg / g raw shrimp waste (d.b.) (ratio of solvent to raw material 3/1). Ultrasound or vortexing gave higher extraction yield than in static conditions, which was 1.5- to 1.8- fold increase, respectively. At the ratio of solvent: dried shrimp = 4: 1, the amount of carotenoid recovered at 60°C for 2 hours reached 57.4 µg / g. However, if the shrimp waste was hydrolyzed with Alcalase at 50°C for 4 hours before extraction by solvent, the amount of carotenoid recovered achieved 149 µg / g of raw materia
A STUDY OF SUSTAINABLE COLORATION OF LYOCELL FABRICS USING EXTRACTS OF TROPICAL ONION SKINS
Get PDFLyocell is considered as a new fiber that represents a milestone in the development of environmentally sustainable textiles. Lyocell is spun from wood pulp cellulose via a green chemical process with NMMO (N-methylmorpholine-N-oxide) solvent. Following the concept of lower the environmental impact of fashion clothing, this study aims to determine the suitable natural dyes recipes with the color extracting from tropical onion skins. Colorants were extracted by dissolving crushed dried onion skins with boiled in water at 100ºC for 20-25 minutes. The ratio of extracting and dyeing are 1:25 and 1:30 respectively. The optimal dyeing condition was found out at 80ºC, 45 minutes with 75% v/v. In addition, a variety of the most commonly used mordants including Potassium aluminum sulfate, Copper (II) sulphate and Iron (II) sulphate were used for mordanting in order to compare the differently mordanted and unmordanted dyed fabrics via color strength (K/S) and CIE L*a*b* color values. It was found that mordant type had an effect on color strength and the color coordinates of fabric dyed with onion skin, which can supply variety of color choices for the same colorants
STUDY ON THE EFFECT OF CALCIUM-ALGINATE AND WHEY PROTEIN ON THE SURVIVAL RATE OF Bifidobacterium bifidum IN MAYONNAISE
Get PDFABSTRACT – QMFS 2019The functional food development by adding probiotic bacteria is getting a lot of concern. In this study, Bifidobacterium bifidum AS 1.1886 was encapsulated in calcium-alginate 2% w/v (C sample) or the mix of calcium-alginate 2% (w/v) and whey protein 1% (w/v) (CW sample) or calcium-alginate 2% (w/v) coated by whey protein 1% (w/v) (CcW sample) by extrusion method, and added to mayonnaise product. The pH changes, the survival rate of probiotic bacteria, and total yeast and mold count during storage, as well as the probiotic survival in simulated gastric medium, were evaluated. The result showed that the pH changes were not significantly different in all mayonnaise samples in this test. The viability of the free probiotic cell was significant decrease about 5.85 log CFU/g compared to 0.26 ÷ 1.14 log CFU/g in encapsulated cell samples after four weeks of storage. None of the free cells survived after six weeks of storage. The total yeast and mold count in samples related to the probiotic count, the viability of probiotic cells higher 6 log CFU/g might be controlling the growth of yeast and molds in mayonnaise. Whey protein has been shown to significantly improve the survival rate of B.bifidum and calcium-alginate coated by whey protein, indicating the most effective protection. The result showed that the application potential of encapsulated probiotic in mayonnaise product
First record of Anselmella malacia Xiao & Huang, 2006 (Hymenoptera: Eulophidae), a new insect pest of water apple (Syzygium samarangense) and its associated parasitoid in Dong Thap Province, Vietnam
Get PDF The eulophid wasp, Anselmella malacia Xiao Huang, 2006 (Hymenoptera: Eulophidae), is reared from fruits of the water apple, Syzygium samarangense, and is reported as an important phytophagous developing as seed-eaters of Syzygium species in Malaysia. Analysing specimens of pest insects infested inside of pear-shaped fruits of the cultivated water apple, S. samarangense, in Dong Thap Province, South Vietnam, a total of four insect species were recorded as the important pests for fruits of six varieties of the cultivated water apples. The hymenoteran wasp, A. malacia, is recorded for the first time from Vietnam. Further evidence is needed to prove A. malacia being an invasive pest in Vietnam. The associated hymenopteran parasitoid assemblage with the fruit infested insect pests is also provided.