It has been well known that the arsenic ions can exist as arsenate (H2AsO4- and H2AsO42-) or arsenite (H3AsO30 and H3AsO3-) species depending on the characteristics of water environment; and the iron oxide materials show very good capacity for arsenic adsorption. In this study, Fe7Mn3Ox/activated rice husk ash (RHA) material is synthesized and characterized. Fe7Mn3Ox/RHA material is introduced as a novel adsorbent with high potential and many advantages, compared to FexOy/RHA material, towards arsenic removal from groundwater by chemical absorption technique. The experimental results showed that 10 wt.% (FeCl3+MnCl2) loading of FexMnyOz on RHA surface had very high arsenic adsorption capacity which is respectively ~1.1, ~1.3 folds higher than those of 10 wt.% (FeCl3) FexOy/RHA and 10 wt.% (MnCl2) MnxOy/RHA adsorbents, for the same amount of adsorbent. The high arsenic absorption capacity of 10 wt.% (FeCl3+MnCl2) Fe7Mn3Ox/RHA adsorbent can be due to the strong interaction of oxide adsorbent and support; and the added manganese oxides into the iron oxide nanostructure for enhancing the positive charge onto nano iron oxide surface.

This paper is concerned with certain properties of chitosan nanoparticles synthesized by ionic gelation method. These synthesized nanoparticles have an average diameter of 12 nm. Their physicochemical properties were tested by different chemical and physical analysis techniques such as FT-IR, XRD, and SEM. In addition, their antibacterial activity was also studied to evaluate the potential applications of chitosan nanoparticles.

This paper presents the results of the effect of aeration rate on the formation and development of aerobic granular sludges in sequencing batch reactor (SBR). The study was conducted under two different aeration rates at 2.5 L/min and 4 L/min with synthetic wastewater prepared from glucose as a main carbon source. The experimental results showed that, at aeration rate of 2.5 L/min, granular sludges were formed after 25 days with a larger size of 4-5 mm but they were uneven and unstable with the dominant growth of filamentous bacteria. Meanwhile, at aeration rate of 4 L/min, aerobic sludges were formed after 35 days with a smaller size in the range of 2-3 mm, but they were rounder and more stable. It was also found that organic matter (COD) removal efficiency was around 85-95% with granular sludge formation.

In recent years, embedded system is an outstanding option to carry out almost all of natural interactive control applications. Besides, it is a contemporary trend towards utilizing natural user interfaces such as head or hand gesture interaction, etc. Existing software solutions; however, still show weak points in processing speed, especially in real-time applications. Therefore, this research proposed a hardware solution by implementing an embedded system on FPGA. This embedded system was built on Altera’s DE2-115 board with input from a 5-Mega pixel camera, which was able to recognize and track hand movement to handle a computer game simultaneously. Preliminary results encourage further research on FPGA-based embedded systems for smart interaction applications.

This paper showed the results of mechanical properties investigation of the composite plates reinforced by the coir fiber plates using calcium carbonate as a filler. In addition, the paper also presented a method for biogas tank production using coir fiber. This method is suitable for small and medium household livestock breeding. Coir fiber from Mo Cay District - Ben Tre province, unsaturated polyester and calcium carbonate were used as the initial materials. The biogas tank was made by hand using the coir fiber mat prepared by hot pressing method with a Pan Stone hot-pressing machine that operates based on the hydraulic system with automatic control and has its heating equipment on the mold. Experiments were conducted to evaluate the tensile and bending properties of the composite plates reinforced by coir fiber mat. The obtained results indicated that the suitable mass fraction of the unsatured polyesters per calcium carbonate for the tank processing was 60% and proper processing steps were proposed to successfully build the biogas tank.

Moodle Quiz is a module of Moodle - a learning management system. Moodle Quiz can help a teacher implement assessments of student learning outcomes in the form of online objective tests easily, quickly, and economically. The functionalities of the Moodle Quiz are stable and have no errors. However, when the number of exam participants is large, the Moodle Quiz often falls into overload. This situation prevents the exam participants from accomplishing their tests and makes examinations fail. This paper will present the result of our research on finding the relation between the workload imposed on Moodle corresponding to a number of users concurrently participating in Moodle Quiz. This result of the research can be used to determine the hardware infrastructure needed for a Moodle system to safely serve a number of users that concurrently participates in the tests on Moodle Quiz.

The study on “Evaluating treatment efficient of fish processing wastewater by trickling filter tank with cocopeat medium and sawdust medium” was done on two lab-scale trickling filter models with the application of local materials as filter to treat fish processing wastewater. Two trickling filter models were set-up at lab-scale conditions. To evaluate wastewater quality, different indicators (including: pH, DO, SS, COD, BOD5, Ntotal, Ptotal, NH4+, and NO3-) were used. When operating the models with input flow-rate of 162 L/m2*day-1 and the return rate of 150%, the effluent wastewater analysis results showed that pH and Ntotal reached the standard of QCVN 11:2008/BTNMT (column A) and Ptotal reached QCVN 40:2011/BTNMT (column B). With input flow-rate of 180 L/ m2*day-1 and the return rate of 150%, the effluent wastewater of model with sawdust medium had pH, Ntotal, SS reached QCVN 11:2008/ BTNMT (column A) and Ptotal reached QCVN 40:2011/BTNMT (column A). In addition, effluent wastewater of model with cocopeat medium had pH, Ntotal, NH4+ reached QCVN 11:2008/BTNMT (column A) and Ptotal reached QCVN 40:2011/BTNMT (column A). The results showed that applying sawdust and cocopeat as medium for trickling filter tank to treat wastewater from fish processing industry is meaningful in terms of financial benefits with high treatment efficient.

One of the main purposes of environemtal modelling is to do spatial and temporal predictions for the values of environmental varaiables over a study site. The environmental models are often developed based on measured data, (inter) relations between environmental variables, and the nature of underlying environmetal processes. In this study, the model for predicting nitrous oxide (N2O) emission was applied with a case study from natural areas of Finland. The prediction outcomes could be affected by errors in calibration data and model’s inputs. Uncertainty quantification in the form of a probability distribution function was used and the Monte Carlo approach was applied for uncertainty propagation analysis. The results show that the prediction of N2O emission in average ranged from 0.4 to 3.1 kgN/ha/year over the natural areas of Finland. The standard deviation of the predition values over the study area varied from 0.1 to 5.5 kgN/ha/year. This interval quantified the uncertainty about the predition outcomes of N2O from the model used for the natural areas in Finland.

Melaleuca cajuputi is a popular tree at the U Minh Thuong National Part, Kien Giang province. Melaleuca forest produces benefits both in terms of social and environmental values. A study on biomass above the ground of the Melaleuca cajuputi forest was conducted to estimate biomass of two groups of trees (i.e. under and over 10 years old). The results showed that, the average density of the trees were about 6.100 – 7.000 trees/ha. The average of tree’s diameter in the group of under and over 10 years old were of 4,56 cm and 5,48 cm, respectively. The older the trees, the greater the growth rate. The Melaleuca cajuputi biomass varied according to parts and age of tree. The highest percentage (of above the ground biomass) was in the stem (with 61,3% and 76,8% trees below and above 10 years old, respectively), successively followed by branches/twigs (with 21.6% and 12,6% trees below and above 10 years old, respectively) and leaves (with 17,1% and 10,6% trees below and over 10 years old, respectively). In addition, there is a close relationship between biomass and diameter and height of tree. Biomass above the ground of tree over 10 years old was greater than that under the 10 years old. The potential biomass were of 65,63 ton/ha and 89,98 ton/ha for the trees below and over 10 years old, respectively.

Interactions of hydrolysis products of cisplatin and its novel derivative cis-[PtCl2(iPram)(Hpz)] with nucleobase guanine are systematically examined for the first time using quantum chemical techniques. The density functional B3LYP method in conjunction with correlation-consistent basis sets, i.e. cc-pVTZ for non-metals and cc-pVTZ-PP for platinum, are employed to investigate thermodynamic parameters, electronic structures, bonding characteristics and spectroscopic properties of several different systems. The calculated results show that these interactions are dominated by electrostatic effects, namely hydrogen bonding, and there exists a flow charge from H atoms of ligands to O6 guanine. Another remarkable finding is that the repalcement of ammine groups by larger ones accompanies with a somewhat moderate interation between PtII and guanine.

A rapid and efficient microwave-assisted synthetic method for the preparation of 2-benzimidazolyl-4-oxo-4H-quinolizine derivatives has been successfully developed. Three 2-(1H-benzimidazol-2-yl)-4H-quinolizin-4-one derivatives were obtained from the reaction between 4-oxo-4H-quinolizine-2-carbaldehyde and ortho-phenylenediamine or ortho-nitroaniline derivatives in the presence of Na2S2O4 or Na2S2O5 as oxidative agents. In all cases, good yields (76-92%) and short reaction time (10 minutes) were observed. The structures of these new 2-(1H-benzimidazol-2-yl)-4H-quinolizin-4-one derivatives were confirmed by 1H-NMR, 13C-NMR and MS spectra

In this reseach, we investigated the distribution of electron gas in the ground state and the first excited state in semi-parabolic quantum wells structure based on the polar materials. We have defined confinement potentials and computed the average energy of an electron by variational method, from which we have determined variational parameters in order to investigate the distribution of electron gas. Especially, this study have identified the role of polarization to the quantum confinement effect of two-dimensional electron gas in the semi-parabolic quantum well based on modulation doping AlN/GaN/AlxGa1-xN material. The obtained results showed that the electronic gas distribution was dominated by the polarization charges existing in the adjacent layers of heterostructure.

Three methanolic extraction methods of 6-gingerol from Ginger root collected from Vi Tan, Hau Giang province have been studied including conventional marceration (TCG6N), mechanical stirring (TCG6K) and ultrasound-assisted extraction (TCG6S). The results showed that the TCG6N method gave highest amount of crude methanol extract (16.36%), while the TCG6S method gave rather lower yield (14.18%) but with shorter extraction time (90 minutes compared with 9 days of the method TCG6N). Column chromatography of ethyl acetate extract using hexane:ethyl acetate (3:2, v/v) as the eluent obtained 6-gingerol in 37.37% yield with the purity reaching 75.73% (determined by GC-MS). Bioactivity evaluation showed that the crude 6-gingerol was inactive toward (PEDV) and H1N1 flu viruses but had weak activity against breast cancer (MCF-7) and Staphylococcus areus.

Diabetes in dogs is a common metabolic disorder and tends to increase recently. In total 1,245 dogs were examined at the veterinary clinic, Can Tho University using history records, clinical diagnosis and blood sugar testing of capillary after 8 hours of feeding by One Touch Basic test paper based on glucose oxydase reaction. There were 2 groups in this study, the first including17 preclinical diabetic dogs and 18 clinical diabetic dogs were treated with Diamicron MR 30 mg and the second including 17 preclinical diabetic dogs and 19 clinical diabetic dogs were treated with Pioglite 30 mg. Results showed that the rate of diabetes in dogs was 5.7 %, in which preclinical diabetes was 47.89 % and 52.11% were clinical diabetes. The popular clinical manifestations were polydipsia, polyphagia, polyuria, weight loss and obesity. Diabetes in dogs was dependent on gender and age. This disease often appeared in dogs from 4 years old and increased in older dogs, which was up to 27.91% in dogs over 10 years. However, diabetes was not dependent on breed group. Using Diamicron MR 30 mg and Pioglite 30 mg could control blood glucose in preclinical diabetic (94.12 %) and clinical diabetic (89.19 %) dogs.

One experiment was implemented by using a 4 x 4 Latin square design on 4 male Lai Sind cattle at 2.5 years of age. Each experimental period was two weeks including the first week for adaptation and the second week for sampling. Four treatments were 140, 170, 200 and 230 g CP/100 kg LW corresponding to CP140, CP170, CP200 and CP230 treatments. The results showed that feed intakes were significantly different (P

The study of “The prevalence of helminth infection and some parameters of blood physiology on chickens in Binh Thuy district” was conducted using the Skrjabin’s necropsy method to identify species of helminths and determine some haematological parameters. A total of 108 chickens were tested for the presence of helminthes. Among them, 8 normal chickens and 8 parasitic chickens were used in the experiment of comparing haematological parameters. The prevalence of parasitic rate in chicken at Binh Thuy district was rather high 25.93%. Chickens were infected with 2 helminthic classes: Nematoda and Cestoda with the infectious rate of 92.86% and 50.00%, respectively. Seven species were found in infected chickens. Among them, five species were belonged to Cestoda class; namely Raillietina tetragona, Raillietina echinobothrida, Raillietina georgiensis, Raillietina penetrans, and Raillietina tinguiana. Only 2 species in Nematoda class namely Heterakis beramporia and Ascaridia galli were found. The highest infectious rate of Heterakis beramporia was 64.29%, following closely by Ascaridia galli with 50%. The infectious rate of Raillietina tetragona and Raillietina echinobothrida was 25.00% and 21,43%, respectively. Infected chickens had a decrease in the number of erythrocytes (2.4±0.54 (106/mm3)) and hemoglobin (6.46±0.95 (g%)), while the number of leukocytes increased to 28.58±4.43 (103/mm3). Hematocrit (20.38±5.10 (%)), M.C.V (85.81±15.82 (fL)), M.C.H (27.52±4.11 (pg)), M.C.H.C (32.82±6.48 g/dL) were fluctuated in normal reference ranges of blood test for chickens.

Carotenoids, an important class of natural pigments, can be used in various fields including medicine, cosmetics, feed stock and food industry. In recent years, the increase of consumer demand for carotenoids obtained from natural sources has promoted major efforts to improve carotenoid production from biological sources, thus opening opportunities for microalgae development. In this study, a hetetotrophic microalga, strain BCM05, with the ability to produce carotenoids was successfully isolated from decayed sonneratia leaves at marine habitat in Ca Mau province. Determination of cell dry weight is a time- consuming process, to overcome this problem, a calibration curve reflecting the relation between the optical density and cell dry weight from BCM05 strain was established. Total carotenoid of strain BCM05 was found to be 7569µg/kg of dry cell weight. The results of the analysis of a part from the region of the 18S rRNA gene showed that there was a 97% similarity of the 18S rRNA gene from BCM05 to Aurantiochytrium sp. B072 (JF266572). Phylogenetic tree analysis by using MEGA software version 5.05 with a high bootstrap value of 1000 replicates, strain BCM05 was determined and named as Aurantiochytrium sp. BCM05. These resuts suggested that this strain could be considered as a potential source for aquaculture feed additives or large scale production of carotenoids.

Phytases are acid phosphatase enzymes, which efficiently cleave phosphate moieties from phytate molecules, thereby generating inorganic phosphate, the essential phosphorus nutrient for organisms. Aspergillus fumigatus is a potential source of extracellular phytase that adopted a special characteristic of high ability in refolding after heat denaturation. This capability is appropriate for feed production. Thus, isolation of A. fumigatus for phytase production is necessary.  The result indicated that there were 8 strains isolated from 5 rice soil samples, however, there were 3 isolates designated as ET3, ET7 and ET8 producing high phytase activity on selective M2 medium at 30ºC. Among them, ET3 showed the best growth at high temperature (45ºC) and its morphological characteristics was similar to morphological characteristics of published A. fumigatus. ET3 was identified by molecular biology based on gene sequencing of ITS region. The result showed that the ET3 isolate belonged to an Aspergiullus fumigatus species that its homology was 98%.

The wastewater discharged by poultry slaughterhouse industries is characterized mainly by complex mixture of fats, proteins, carbohydrates from meat, blood, and feather, resulting in much higher biochemical oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS). In this study, using nitrogen removal Pseudomonas stutzeri strain D3b and polyphosphate-accumulating Bacillus subtilis strain DTT001L to remove nitrogen and phosphorus, especially ammonium (NH4+) and dissolved phosphate (orthophosphate-PO43-) in the treatment of poultry slaughterhouse wastewater was performed. The results showed that the bacterial population varied from 6.68-7.14 log10cfu/mL in aerobic conditions in 10-liter containers when wastewater was supplemented with glucose (2.5g/L) and biological fixed contact material (MFCM), subsequently the removal efficiency of NH4+ was from 98.9% to 100% and PO43- was 90.6%-100%, pH value of wastewater from 7 to 9 after 1 day but the values of COD, TSS, TN were higher than the standard of QCVN40:2011/BTNMT. Application of this model in two experiments with higher volume (100-L containers), the results showed that concentrations of NH4+, PO43-, TN, TP, COD, TSS, N-NO2-, N-NO3- in poultry slaughterhouse wastewater met the requirements of the Vietnamese standard (A level of QCVN40: 2011/BTNMT) after 24 hours in experimental 100-L container model.

Phytase is a group of enzymes that is able to release phosphorus from phytate so that it can be easily digested, so phytase is largely used in animal feed. Aspergillus fumigatus ET3 appeared to have high potential for phytase production. In this study, the growth conditions to improve the enzyme production of this new A. fumigatus ET3 were investigated. The result showed that wheat was a suitable substrate for biosynthesis of phytate from this fungus. Furthermore, optimum conditions for high phytase production from this species were pH 4, spore density about 108/mL, incubation time of 2 days and incubation temperature of 35oC.

Piggy wastewater after biogas still contains high organic and inorganic pollutants and it must be treated before discharging into environment. Bioflocculation is extracellular polymer, which is produced by microorganisms. It is safety, strong effect, biodegradable and harmless to human and environment in comparison to conventional synthesis flocculant. Therefore they were applied for treating piggy wastewater after biogas system. Bacillus aryabhattai strain KG12S was isolated from piggery wastewater in Kien Giang province, Vietnam. The optimal medium for Bacillus aryabhattai strain KG12S consisted of glucose (1,12%), glutamate (5,7%), and K2HPO4 (0,4%) + KH2PO4 (0,8%) at pH 6 with kaolin solution after 5 minutes together with CaCl2 solution and 0.2% inoculant (bacterial liquid) increased the flocculanting activity up to 96.87%. Results from applying this strain for treating piggy wastewater showed that Chemical Oxygen Demand (COD), total solid suspension (TSS), total nitrogen, total phosphorus and ammonium concentrations were reduced 50,85%, 67,21%, 75,00%, 85,42% and 77,78%; in comparison to initial concentrations, respectively. Especially, total phosphate parameters met the requirement of Vietnamese standard (QCVN_ 40/2011/BTNMT).

Thermal and combined high pressure-thermal degradation kinetics of ascorbic acid in sodium acetate buffer (0.2 M, pH 5.0) and sodium phosphate buffer (0.1 M, pH 7.0) were studied at different molar ratios between oxygen and ascorbic acid. Thermal degradation of ascorbic acid could be described by a biphasic model, suggesting that the degradation occurred through aerobic and anaerobic pathways. It was observed that the ascorbic acid degradation had already occurred during pressure build up probably due to oxidation (aerobic degradation). When the oxygen was totally used up, the anaerobic degradation dominated and took place much more slowly than aerobic degradation. Thus, it seemed that ascorbic acid was stable at pressures up to 700 MPa combined with temperatures up to 70°C (up to 100 min of treatment after pressure build up). However, ascorbic acid was degraded at extreme pressure temperature combinations such as temperatures above 70°C combined with pressures above 700 MPa. The molar ratio between ascorbic acid and oxygen was an important parameter to estimate the proportion of ascorbic acid aerobic degradation and to determine the concentration of ascorbic acid needed to protect other nutrients during processing.

The rice starch was hydrolysed by two-step enzymatic treatment using α-amylase and gluco-amylase. The effects of temperature, enzyme dose and time on hydrolysis efficiency (viscosity and DE index) were investigated. The Central composite design (CCD) and response surface methodology were used for the experimental design and results analysis. The results showed that all three factors (including temperature, enzyme dose and time) had significantly effect on viscosity and DE index in liquefaction and sacharification. In both hydrolysis steps, the models were established with 32 experiments for each step. The response surface model predicted the minimum viscosity to be 30.899 cP at a temperature of 74,71oC, α-amylase dose 0.13% and hydrolysis time of 40.54 minutes. The maximum DE index (77.382%) could be obtained at optimal conditions (at temperature of 60.39°C in 210 minutes and gluco-amylase dose of 0.077%). Verification results showed the value of theoretical viscosity and DE index corresponding to practical value.

The objective of the work was to use the method of Principle Component Analysis (PCA), Logistic Regression and Preference Map Analysis to describe the sensory attributes of the rice milk products prepared with the combination of added cream milk and total soluble solid content present in rice milk. Panellists were trained to evaluate various attributes specially color, flavor, taste, appearance of the rice milk products and overall acceptability of the consumers. Principal component analysis identified two significant principal components that accounted for 89.86% of the variance in the sensory attribute data. Principal component scores indicated that the important sensory attribute of rice milk primarily corresponded to sweetness, fatty taste, rice flavor, cow milk flavor, milk skin, sedimentation, brown color. Overall acceptibility of product was modelled (logistic regression analysis) as a function of fat and total soluble solid content in rice milk product. The P-value for the model is less than 0.05, there is a statistically significant relationship between the variables at the 95.0% confidence level. These findings demonstrate the utility of PCA and logistic regression analysis for identifying and measuring the rice milk product attributes that are important for consumer acceptability and preference.

The aim of our study was to assess the impact of a pulsed light (PL) technology on B. subtilis growth on two model matrixes, through bacterial inactivation and cell integrity. First, the effect of PL treatment (light flux of 0.6 J.cm-2/flash) on B. subtilis vegetative cells in liquid state (DO580nm = 0.8) was evaluated. We found that PL treatment leaded to 8 log reduction of B. subtilis vegetative cells while bacterial morphology was not affected. When DNA extract from B. subtilis vegetative cells was analyzed, a significant difference was found between the control and the PL-treated samples. Second, spices, among which ground caraway, ground red pepper and ground black pepper were artificially inoculated with a known concentration of B. subtilis in vegetative state (at logarithmic phase) and then the spices were exposed to PL (light flux of 1 J.cm-2/flash). In this case, PL treatment leaded to a bacterial reduction of about 1 log and serious damage of the microorganism’s parietal structure occurred. To conclude, this work highlights that pulsed light had a potential for inactivation of B. subtilis in both, liquid and dry state but through different mechanisms.

A study on enzymatic hydrolysis of protein from head meat of Black Tiger shrimp using intracelllar protease was carried out. Factors affecting the hydrolysis of protein including time and pH were investigated. Thermal pre-treatment conditions to activate the intracellular protease were optimized using response surface method consisting of 24 experiments. The experimental results showed that, the optimal hydrolysis time for the best quality product was 8 hours. The optimal conditions for the best hydrolysis included pH of 9.0 combined with the pre-treatment temperature of 50.73°C and the pre-treatment time of 4.43 minutes.

The study was conducted to analyze the difficulties and concerns of farmers in 5 farming models, such as Rice monoculture, Aquaculture, Rice-aquaculture, Rice-upland crop, and Rice-Upland crop-Aquaculture. Results showed that rice was the common crop in farming models and farmers had farming experiences. The diversification of crops, aquaculture tended to help farmers achieving higher profits. The difficulties of farmers in farming models were focused on Market issues, Farming environment and Management of production. In farming models with rice cultivation, the Money saving on farm was predicted by Farming season, Extension training, Water source for farming, Water quality for farming, and Health of household. In Aquaculture model, the Money saving on farm was predicted by Extension training and Water quality for farming. The factor analysis identified three factors for farmer concerns, which were Household safety, Farming technique improvement, and Stock and Water requirement.

The study was carried out to determine the effect of day-old seedlings on adventitious shoot regeneration from cotyledonary node explants and the optimum concentrations of plant growth regulators (BA, Kinetin and IBA) for shoot establishment, multiplication and rooting of Momordica charantia L. in vitro. Experiments were conducted in Laboratory of Plant Tissue Culture, Department of Plant Physiology and Biochemistry, College of Agriculture and Applied Biology, Can Tho University, from April 2013 to Match 2014. The results showed that: (1) the cotyledonary sections of the seedlings at 12 days after germination (in the dark) showed a high rate of shoot regeneration (about 93.8%) after three weeks cultured on MS medium supplemented with BA 2.5 mg/L and these shoots grew very well; (2) MS medium supplemented with BA 1 mg/L + kinetin 0.2 mg/L was effective for the rapid proliferation of shoots in vitro; and (3) the root induction was observed on MS medium with 2 g/L activated charcoal and IBA (0-1 mg/L). The average rooting frequency was 85.4-96.9% after three weeks cultured.

The black spot disease is a major problem in the production of field-grown roses, as it causes significant losses of yields and quality. In the present study, 20 rose varieties were used to identify the black spot disease resistant varieties by using two SSR molecular markers 155SSR and 69Mic for the Rdr1 resistant gene.  Results showed that 13 out of 20 varieties were resistant to black spot disease and 7 out of 20 varieties were susceptible in the field condition. There were 12 out of 13 resistant varieties linked to Rdr1 gene through 155SSR (157 bp) and 69Mic markers (249 bp). Mussay was the only field-resistant variety which was not identified by Rdr1 locus. Four susceptible varieties were also screened by these markers. These results indicated that 155SSR and 69Mic are valuable SSR markers to identify the resistant varieties to black spot disease in rose and very useful for breeding program of black spot disease resistance.

This study was aimed to determine the appropriate period for harvesting fruits of Hoa Loc mango in the on-season (Apr.-May), late-season (Jul.-Sep.), and off-season (Dec.-Jan.) harvesting time. An experiment was carried out from May 2012 to January 2013 at three mango orchards located in Cai Be district, Tien Giang province. At each orchard, six mango trees at the age of 8-10 year-old were selected. Fruits of Hoa Loc mango were harvested at 70, 75, 80, 85, 90, and 95 days after fruit set (DAFS). At each harvesting period, three fruits per tree were sampled to determine weight, skin colour, and fruit quality. Results showed that the mango fruit matured at 80-90 DAFS and subsequently shifted to the  ripening stage. Fruits should be harvested at 85-90 DAFS in the on-season and at 80-85 DAFS in the off- and late-seasons because at these times the quality and fruit parameters fluctuated negligibly, viz. 20-21% Brix, 22-28% dry material, 80-82% fruit flesh and 1.02 fruit density, and the fruit reached highest quality.

“One must do, five reductions” technique (1M5R) was certified as a new technology in rice production. However, expansion and effectiveness of this technique were various depending on many factors such as water management, cultivating methods and farm management. Of which, organisational pattern of production was one of the most important factors directly impacted upon the 1M5R’s effectiveness. This paper analysed and compared the economic efficiency between two farmer groups applied 1M5R, individual and collective production. Results showed that the collective production form (cooperatives) helped farmers to reduce their production costs by applying the 1M5R technique. Nevertheless, success of this technique changed significantly according to local specific conditions. Results of the study give useful information for planning and expanding the 1M5R in order to save production costs and to increase in net income for rice farmers.

Rice is the main food crop which nurtures for more than a half of world population and grown widely in Asia. In the southern of Viet Nam, Cuu Long Delta is the major region of country rice production located in the low topography and frequently flooded in annual rainy season causing many problems for rice farming. One of an adaptive mechanism of rice to submergence is to reduce elongation and save energy by slowing down the metabolic process. Silver is the well-known element which inhibits ethylene biosynthesis that plays a diverse function in plant biology. This experiment aimed to find out the appropriate concentration of AgNO3 to enhance rice tolerance to submergence of some popular rice cultivars and investigate total soluble sugars in plants after drainage and measure oxygen consumption during submergence. Experimental results showed that AgNO3 at 3 mg/L rescued 83% of rice seedlings after 7 days of submergence in contrast to 29% of the control. After a 7 day submergence with water, 70% of OM6976 seedlings survived as the highest ratio in comparison to the lowest one, 47% of OM4218, but those rice cultivars treated with AgNO3 in the same manner resulted in equal survival of 75% in average. After submergence, the dissolved oxygen decreased gradually but in the present of AgNO3 in the solution its level maintained; this could be a possible factor to prolong the endurance ability of rice seedlings together with less utility of total soluble sugars during anaerobic metabolism.

The main objective of this study was to find effective fruit bagging methods at three different maturity stages based on the fruit yield and postharvest quality of langsat fruits. From April to August of 2013 experiments were conducted on 11-year old langsat trees growing at Luc Si Thanh, Tra On district, Vinh Long province, Vietnam. Experiments were done using a completely randomized design (CRD) with two factors: (1) type of fruit bagging including non-bagged fruit cluster as control treatment and a total of 12 different types (five PE bags of different colors and materials (with or without newspaper inside), white and yellow paper bag) and (2) tested on plants at three different maturity stages (14, 28 and 42 days after fruit set).. Each treatment was replicated 4 times using a single cluster of fruits. Results showed that in terms of maturity stage, the most appropriate time for fruit bagging was at 14 days after fruit set.  Also, in terms of bagging types, yellow and white paper bags appeared to be the most effective. Bagging of fruit clusters with these papers were effective for maintaining the number of fruits on each cluster (>21 fruits/cluster), increasing the fruit weight, reducing the percentage of fruit drop and inhibiting the development of sooty mold on fruits. The treatments also increased the brightness of fruit skin color and kept some quality indexes, such as the Brix ratio and stable pH.

Experiments were conducted in the randomized complete block design with four treatments and four replications, such as plots of N omission but full in P and K fertilizers, P omission but full in N and K, K omission but full in N and P, and full in N, P and K. After the optimum fertilizer formula was found, the application models were carried out by dividing the farmer’s field in two parts: (1) fertilizer management based on the site specific nutrients management (SSNM) method, while (2) fertilizer management based on the farmer practice (QTND). Results showed that: (a) in Spring-Winter crop: the amounts of NPK nutrients supplied from solid was 65 kg N + 33 kg P2O5+ 115 kg K2O and the proposed formula was 90 kg N + 36 kg P2O5+ 22 kg K2O/ha; and (b) in Early Summer-Autumn: 49 kg N + 26 kg P2O5 + 88 kg K2O and 85 kg N + 40 kg P2O5 + 28 kg K2O/ha, respectively. Fertilizer recommendation based on SSNM has increased in crop yield up to 0.33-0.48t/ha and farmers applied more fertilizers in QTND than those of SSNM plots for both season with 6-9 kg N/ha, 13-18 kg P2O5 and 27-28 kg K2O.

White leg shrimp culture is one of the most important aquaculture systems in the coastal areas of Ca Mau province. In order to evaluate technical and economic aspects and to identify advantages and disadvantages of white leg shrimp farming system, this study was conducted from December 2013 to May 2014 through interviewing 34 households culturing white leg shrimps. Results showed that the average culture area for each household was 0.72 ha and the average pond area was 0.22 ha/pond. The post larvae in stages of PL8 to PL12 sourced from central provinces of Vietnam were stocked at density of 74.7 PL/m2. Shrimps were mainly fed with pellet feed. After culture period of 87.4±16.4 days, shrimps were harvested with body weight of 92.4 individuals/kg, survival rate around 71%, feed conversion ratio (FCR) was 1.07 and average yield of 6,366 kg/ha/crop. Results showed that the production cost of 390 million VND/ha/crop, gross income of 1048 million VND/ha/crop, net income was rather high of 657 million VND/ha/crop and cost benefit ratio was 1.66. Some major difficulties were found from this system such as high feed cost, lack of funds, shrimp disease and high PL price.

This study was implemented in order to evaluate the cost benefit and technical barriers of black tiger shrimp and mud crab integrated culture system by direct interviewing 40 farmers in Nam Can district, Ca Mau province from 08/2014 to 12/2014. The results showed that pond area was 1.5 ha in average, water surrounding ditch area accounted for 28.6%, water depth was 1.1 m in ditch and 0.5 meter in the central platform. Number of seed stocking times for shrimp and crab was 5.8 and 4.6 times per year, respectively, with the density coresponding to 19.0 shrimp/m2 and 0.5 crab/m2. The average yield capacity of black tiger shrimp, crab, natural shrimp and fish was 365; 76.9; 109 and 40.3 kg/ha/year, respectively. The average total cost was 26.6 millions VND/ha/year; the average total income was 118.8 millions VND/ha/year; the net profit was very high, 91.3 millions VND/ha/year and the cost benefit ratio was 3.7. Three factors enhanced the efficiency of the integrated farming were identified (i) application of probiotics; (ii) not exceed 8 times of shrimp seed stocking per year and (iii) not more than 3 times of crab seed stocking per year. Results of this study provided basic knowledge for improvement of tiger shrimp and mud crab integrated farming system in the Mekong Delta in generally and Ca Mau province in particularly.

This study estimated realized heritability of 6-month weight of square-head climbing perch (Anabas estudineus) selected based on two cut-off values (5% and 25% of the normal distribution of the G1 population’s weight) and investigated effects of broodstock age on offspring’s growth. Four fish treatments included offspring from two selected (G2-CL1 and G2-CL2, respectively) and non-selected (G2-NN) 10- month old G1 parents, and offspring (G1-0) from the first generation with 26 months old. Two-month fingerlings (4.6 - 6.4g) were stocked in hapa nets at the density of 100 individuals/2m2with 4 replications for each treatment. Fish were fed commercial feed with decreasing levels of protein (40% to 30%) by months of culture. After 4 months, survival rates were similar among treatments (P>0.05), ranging from 82.8 to 94.8%. Feed conversion ratios (FCR) in selected groups (1.53 - 1.58) were lower than non-selected fish (1.82±0.49). Growth of fish in G2-CL1 was highest, where the final weight (126.4±25.2g) increased 43.6% compared to G2-NN. Realized heritability of body weight was 0.31±0.16 for 5% selected group and nearly zero for 25% selected group. Broodstock ages (10 and 26 months) did not significantly affect growth and FCR of climbing perch.

Clarias gracilentus, the new species belonging to Clariidae family was found in Phu Quoc island, Kien Giang province, Vietnam by the year 2011. In order to determine the breeding capability in the confined condition, broodstock with body weight of 192.1 ± 54.3 g were reared in a recirculation system and fed with commercial pellet (41% CP) in 8 months before induced to spawn. Preliminary results showed that broodfish adapted well and reached full sexual maturity in the captive condition. To induced ovulation, a series treatment with single hormone of carp pituitary gland (PG), human chorionic gonadotropin (hCG), Ovaprim, Luteinizing Hormone - Releasing Hormone analogue (LHRHa) and the combinations of PG with Ovaprim, hCG or LHRHa were tested. Results showed that single hormone of PG, hCG or LHRHa plus DOM was induced final maturation and ovulation process in which single injection of PG at the dose of 8 mg/kg of female body weight obtained a good results with 32.7±10.7% and 69.1±11.2% in fertilization and survival rates, repectively. Among treatments using combination of PG with other hormones, fish received 2 successive injections at 8 hours interval, a preliminary dose with 2 mg PG/kg and decisive dose with 4,000 IU hCG/kg of female body weight, gave the best results with highest fertilization and hatching rates. These preliminary results give promising prospects for a mass seed production of this species in future.

Recombinant VP28 (rVP28) of WSSV has been shown in different expression systems such as Gram-negative bacteria (Escherichia coli), gram-positive bacteria, insect’s cell, yeast and silkworm. Many studies have been conducted assessing the impact of VP28 against WSSV on Procambarus clarkii, Fenneropenaeus chinensis, Penaeus japonicus, Litopenaeus vannamei. In this study, Bacillus subtilis displaying VP28 on the spore surface was tested and used as a vaccine against WSSV on black tiger shrimp (Penaeus monodon). The shrimp were fed by food containing B. subtilis spores displaying VP28 under CotB-VP28, CotB-GST-VP28 within 7 days, followed by a challenge experiment with WSSV. The effectiveness of the spore was assessed by: (i) the number of immunological parameters uncluding total hemocyte count, hemocyte differential, phenoloxidase activity, and superoxide dismutase activity, and (ii) the survival rate of shrimps after being challenged with WSSV. The results showed that after 14 days of infection, shrimp fed with food containing CotB-VP28, CotB-GST-VP28 had a high survival rate compared to the control group, PY79. In particular, the relative percentage survival (RPS) was obtained in the group of shrimp fed with food containing CotB-VP28 at the highest level of 53.4%.

This study aimed to investigate the effects of stocking densities on survival rate and growth performance of white leg shrimp postlarvae (PL) following application of bio-floc technology. The experiment included five treatments at different stocking densities as follow: (i) 500 PL/m³, (ii) 1.000 PL/m³, (iii) 2.000 PL/m³, (iv) 3.000 PL/m³ and (v) 4.000 PL/m³. Postlarvae with initial weight (0.03g) were stocked in composite tanks (0.5 m3) at salinity of 15 ‰. The experiment was lasted for 28 days. Two sources of carbohydrate (Cassava and soybean powder) were used to facilitate bio-floc forming at C/N ratio above 12. Results showed that the highest bio-floc volume ranged from 9.1±4.1 to 11.8±6.5 mL/L, and there was no significant difference in bio-floc volume among treatments (p>0.05). After 28 days length (4.69 ± 0.43 mm) and weight (0.70 ± 0.15 g) of shrimp in treatment 3 was significantly higher than those of treatment 4 and 5 (p0.05). The lowest survival rate was found in treatment 5 (74.8 ± 5.4%) which was significantly lower than shrimp survival rate in other treatments (p

The technical assessment of cage culture in Ngang island, Nam Du Islands, Kien Hai District, Kien Giang province was carried out in order to provide basis knowledge to improve marine cage aquaculture as well as planning and management. This study was conducted through interviewing 60 cobia and grouper farms from June to August, 2013. In cobia cage culture, the average cage size was 85.8 m3 with stocking density at 2.54 ind/m3. The average fingerling size was 20.9 cm and culture period from 8-12 months depending on fingerling size. Harvest size ranged from 5.0-8.5 kg/ind. and survival rate was 75% (with the range from35-95%) and FCR was 10.1. The average productivity and net income was 1,296 kg/100 m3 and 4.71 million VND/100m3, with the cost benefit ratio was 0.03. In grouper cage aquaculture, the average cage size was 68.3 m3 with stocking density at 6.96 ind/m3. The average fingerling size was15.3 cm and harvest size was 0.8-1.0 kg/ind. The culture period lasted for 8-12 months depending on fingerling size of stocking. Survival rate was 45.5% and FCR was 10.7. The average productivity and net income was 286 kg/100 m3 and 19.1 million VND/100 m3 with the cost benefit ratio was 0.18. In general, cage culture of grouper and cobia can get high net income but showing unstable economic efficiency.

The study was conducted with two experiments to determine the ability of using bread yeast and optimal harvesting rate in mass culture of copepod Schmackeria dubia. Experiment 1 was randomly designed with 5 treatments with 6 replicates each including (i) 100 % algae (Chaetoceros calcitrans), (ii) 100 % yeast, (iii) 25 % algae and 75 % yeast, (iv) 50 % algae and 50 % yeats; (v) 75 % algae and 25 % yeats. Experiment 2 was set up with 4 treatments of different harvesting rates of biomass including 0, 15, 20 and 30%. Copepods were fed with 100% algae (from Exp. 1).  The biomass was harvested every three days when copepod density reached 5,000 to 6,000 ind/L. The experiments were designed in 1L beaker system with copepod density of 1 ind/mL at salinity of 20 ppt and fed with Chaetoceros calcitrans. The results showed that after 30 days of culture, highest density of copepods (9,200 ± 938 ind/mL) was obtained at the day 6th in treatment fed with 100% algae in Exp. 1. The combination ratio of 75% algae and 25% yeast resulted in best result (higher density compared to other combination ratio). Periodic harvest of 30% of biomass resulted in highest recruitment and density, up to 11.510±817 inds/mL.