When using common light microscopes, focusing is usually performed manually therefore it is time consuming and eye fatigue may be caused after a period of focusing especially through the microscope eyepieces. One solution to this problem is using an autofocusing system based on images of the observed object at consecutive focusing positions along the optical axis of the microscope. In order to design this autofocusing system, this study aims to evaluate well-known autofocus algorithms. A number of eight autofocus algorithms were evaluated with two sets of coconut fiber and algae images that had been captured using an available inverted light microscope with an 10x objective lens. Experimental results showed that the algorithm using autocorrelation as the focus measure function outperformed other algorithms and could be implemented in an autofocusing system.

Due to intensive drought and saltwater intrusion, this paper is devoted to analysis, evaluation and selection on the most effective emerging desalination technologies for brackish underground water desalination in order to meet fresh water requirements of rural villages in Mekong Delta. Based on analysis and comparison on the desalination technologies used in Vietnam and worldwide in context of rural villages in Mekong Delta, the paper demonstrated that electrodialysis technology has a greatest potential for application.

Chemical composition and anti-microbial activity of essential oil from leaves of Piper betel L. collected from Hau Giang province has been investigated. Highest yield of oil (0.63 %) of P. betel L. leaves was successfully extracted by steam distillation. By using gas chromatography - mass spectrometry analysis (GC-MS), we have confirmed that the main component of P. betel L. essential oil is 4-Allyl-1,2-diacetoxybenzene, with content up to 34.55%. The in vitro anti-microbial activity was evaluated by Minimum Inhibitory Concentration (MIC) method. The results showed that the essential oil from betel leaves inhibited the growth of 3 microorganisms species: B. subtillis, F. oxysporum and A. niger with the MIC values of100, 200 and 200 μg/mL, respectively.

Concrete mix design for normal concrete and concrete including rice husk ash based on the densified mixture design algorithm is investigated. The major difference from other mixture design algorithms is that instead of partial replacement of cement, the concrete mix design method incorporating pozzolanic material is used to fill the void of aggregates and hence increase the density of the aggregate system. The purpose of such action is to reduce the cement paste content as low as possible for design properties such as workability, strength, and durability. Using it provides several advantages, such as improved strength and durability properties, and environmental benefits related to the disposal of waste materials and to reduced carbon dioxide emissions.

Sprouts are clean agricultural products that provide nutrients for the human body development and help to prevent diseases. “The automatic clean sprouts nursery system” can be used to automatically sprout different types of vegetables while ensuring the quality of the sprouts, reducing the harvest time and the labor effort. To build an effective model of sprout nursery system, the ideal parameters of the environment for each type of vegetable sprouts should be known so that the sprout nursery system can be designed to simulate such environment and follow a reasonable watering process. The system is capable of fully automatic operation with temperature and humidity reserved or can be set operating modes by the user in real time.

The objective of the article is to propose a suitable management model which could be used to exploit rich and diversified data in different formats (i.e. text and spreadsheet). Besides, we also propose specific solutions based on a common Big Data platform, including: (1) HDFS (Hadoop Distributed File System) of Hadoop, which could be used in file management, (2) Lucene, which could be used to establish reversed indexing for text and (3) Apache Solr, which could be used to support reversed indexing management mechanism, full text searching and advanced searching functions. This article also presents experimental results, aggregates statistical results and displays statistical chart of applying the model into the analysis of trends in scientific research at Can Tho University.

The research approach is to use the Nomalized Difference Vegatation Index (NDVI) for monitoring the rice crop pattern; Temperature Vegetation Dryness Index (TDVI) for estimating the land surface moisture;  and time series data of EVI, LSWI and DVEL were used to map flood distribution. By classification time series data extracted from MODIS images from 2000 to 2011,  the study has identified rice cultivation areas frequently affected by drought or flood in the Vietnamese Mekong Delta. This research also determined the suitable rice farming systems for 9 agricultural ecology zones as well as the solutions to intergate different indices as NDVI, TVDI and LSWI for monitoring rice farming system related to drought and flood impacts. The datasets of rice farming system, drought and flood in the Vietnamese Mekong Delta and the approach using remote sensing technology achieved from this research are helpful that can be applied for agriculture management and land use planning in this area.

Mangroves have an important role and great function in environmental protection and coastal ecosystem. Mangrove forest also has a role of climate regulation, reducing greenhouse gases and contributing to climate change mitigation. Therefore, forest biomass estimation is nescessary for suitable forest management. This study apply three types of low and medium resolution imagery (including MODIS, SPOT and LANDSAT) with the application of NDVI index (Normalized Difference Vegetation Index) to determine mangrove forest species distribution in the Dat Mui Commune, Ngoc Hien district, Ca Mau province. The study area are dominated by four main species of mangrove forest, including: Rhizophora apiculata blume, Avicenna alba, mixed forest and combination system of shirmp and mangrove forest. The result shows that two of three images used to determine mangrove forest are of high reliability (i.e. 94.72 % and 96.14 % of SPOT and LANDSAT images, respectively) and of low reliability (i.e. 34.3% of the MODIS image). Total mangrove area is 9.555,21 ha in which the shirmp and mangrove forest combination is of the greatest (approximately, 48,48%); next to that, rhizophora species (27,2%) and avicenna species (20,6%) are of the sequences while the lowest area is of the mixed forest (4,25%). Moreover, fresh biomass of each forest species is identified based on ages and trunk diameters with the greatest distribution on avicenna species (214,92 kg/ha/year), rhizophora species (188,42 kg/ha/year) and the combination system of shirmp and mangrove forest (113,05 kg/ha/year) with ratio between mangrove forest and shirmp at 6:4.

The study presented the development of a two-dimensional (2D) domain nested in a one-dimensional (1D) hydraulic modelling by a new version of the HEC-RAS hydraulics model (version 5.0) in a river section of the Hau River running along the Can Tho city. The main objective of the research was to assess the applicability of the 2D hydraulic model nested in a 1D hydraulic model in the study river section to provide better understanding on hydraulic properties of surface water flow (e.g. flow direction and velocity at each considered position) during the dry period (from April to May in 2012). Input data of the 2D domain were developed based on the outputs of the 1D model (which was fully calibrated and validated). The study set a stage for subsequent studies about potential impacts of flow on river morphological changes.

Landfill of sludge from waste water treatment plants is harmful to environment. Therefore, the study aimed at investigating chemical and nutritional properties of sludge from wastewater treatment plants of beer and seafood processing factories for reusing in producing organic fertilizer. Sludge samples were collected at beer factories in Soc Trang, Tien Giang, and Bac Lieu provinces and at seafood processing factories in Dong Thap, An Giang, Hau Giang, Tien Giang, and Bac Lieu provinces for determination of chemical, nutritional and biological properties. Results showed that pH of both kinds of sludge was slightly acidic to neutral (6,15-7,6). Electrical conductivity values were suitable (ranging from 2,1 to 4,56mS/cm). Organic carbon contents were at high level (21,53-42,81%C). Total Nitrogen and Phosphorus contents in both sludges were high, at 1,81-4,65%N and 3,31-7,29%P2O5 respectively, but total Potassium content was low at 0,16-0,74% K2O for all sludge samples. Cd and Pb concentrations and Salmonella population in sludge were below the standard issued by the Ministry of Agriculture and Rural Development, except for the samples at seafood processing factory in Bac Lieu province. E.coli and Coliform population exceeded the standard limits. Total Mn, Zn, Cu in sludges were suitable for reusing in composting. Therefore, both of the sludges from wastewater treatment plants of beer and seafood processing factories could be reused for organic composting.

The article introduces a method of statistical analysis, which is applied appropriately for data having cyclical and “seasonal” characteristics. The data will be modeled in the form of the trend regression model, which is established from the time variable and "season pseudo" variables.  The method is illustrated interestingly on the data collected at the canteen of Can Tho University. We also test this data for the ARIMA model, a model in time series analysis.

From leaves and terminal branches of Melaleuca alternifolia grown in Tien Giang province, the Melaleuca alternifolia oil - Tea Tree oil (TTO) was extracted by steam distillation method. Extraction process parameters were studied including distillation time and temperature and material preservation time. Chemical ingredients of TTO were identified by modern analytical method GC-MS. Collected TTO was used as the main antibacterial ingredient in mouthwash product. The results showed that, the prime conditions for distillation were at 100oC and within 100 minutes. The average distillation productivity of TTO was 4.91% (wt/wt) with the main components including Terpinen-4-ol (36%), γ-Terpinene (17.8%) and 1,8-Cineole (10%) which reached the ISO 4730:2004 standard. The obtained mouthwash product possessed the same antibiotic activity as commercial product against Staphylococcus aureus and Pseudomonas aeruginosa. These results contributed to find a new application of TTO which would increase its economic value in Viet Nam.

Land snail samples were collected qualitatively and quantitative in October, November 2013 and October 2014 at 49 locations of three islands (Hon Tre, Lai Son, and An Son islands) with four different habitats (natural forest, planted forest, long-term trees garden and short-term trees garden). Through analysis of 4,471 land snail individuals, in which 833 individuals were collected in 102 quantitative sites, the results showed that there were 25 species, classified into 20 genera, 12 families, 2 subclasses. Among these species, 2 species were firstly found in Vietnam (Quirosella knudseni Clench, 1958; Pleurodiscus balmei (Potiez & Michaud, 1838)), 9 species were firstly found in Mekong Delta (Vietnam) and 6 taxa were unidentified to species the scientific name. The subclass Pulmonata had the most various species (76%) and the families Cyclophoridae and Camaenidea had the most numerous species (5 species). The distribution area of land snails in the islands of Kien Hai district, Kien Giang province seemed to be more similar to surrounding nations than that in the North of Vietnam. Species composition, diversity index and density of snail were found to decrease as going from near to far islands with respect to the mainland. Cyclotus fasciatus Von Martens, 1864 and Quantula striata (Gray, 1834) were the dominant species.

Search for new derivatives of platinum being more effective in cancer treatment has received much attention in recent times. It is considered that oxaliplatin is an antitumor derivative in cancers, which resist cisplatin, through in vitro and in vivo assays. However, studies on its reaction mechanism have not been elucidated. In this work, quantum chemical calculations are employed to examine interactions of hydrolysis products of oxaliplatin with the base site of DNA using guanine and guanosine as the model reactants. Thermodynamic parameters, electronic structures, bonding characteristics and spectroscopic properties of the resulting complexes are investigated using the B3LYP functional along with correlation-consistent basis sets. The calculated results show that these interactions are dominated by electrostatic effects, namely hydrogen bonding. In addition, there exists a charge flow from H atoms of ligands to O guanine, which stabilizes the resulting structures.

The study was conducted to determine the effects of mineral – vitamin premix on blood characteristics and growth performance  of pigs. The experimental pigs were divided into two groups (with or without mineral – vitamin premix supplementation) and four replicates on eight growing pigs with average initial weight of 40 ± 1,26  kg. Collected parameters were the hematological indices of blood and growth parameters including final body weight gain, cummulative growth and FCR. The results showed that the number and formular of white blood cells did not differ (p >0.05) between treaments, while the number of red blood cells and hematocrit tended to be higher than that in treatment group. The final body weight, cumulative growth, daily weight gain of pigs in treatment group were higher (p

The study “Application of  bromelain for amino-rich powder production from shell of shrimp’s head (Litopenaeus vannamei)” was carried out with the aim of producing amino-rich powder from protein of shell of shrimp’s head. The evaluated result of initial raw materials showed that the total protein and the humidity of shell of shrimp’s head were 15.31% and 74.78%, respectively, and the specific activity of  bromelain extracted from pineapple shell was 10.68 U.mg-1. The investigation of the effect of  concentration, temperature, time and pH on the shell of shrimp’s head protein hydrolysis process indicated that the appropriate conditions for hydrolyzing two gram of shell of shrimp’s head by bromelain (with 10.68 U.mg – 1 specific activity) were conducted in buffer phosphate pH 8, at temperature 45oC for 4 hours with the produced amount of highest amino content (4.679 ± 0,101 mgN/mL) and lowest ammonia content (0.256 mgN/m), respectively. The analytical result of molecular weight protein by the method of sodium dodecyl sulphate polyacrylamide gel elctrophoresis (SDS - PAGE) also showed that the majority of protein from shell of shrimp’s head was hydrolyzed effectively by bromelain of pineaple shell juice and created into short sequences of polypeptide which are mostly smaller than 14.4 kDa.

Garlic storage is important to provide products for fresh and processing food market. Determination of maturity and prolonging the storage time of garlic bulbs after harvest were carried out the basis on investigation of (i) time of growth (120 to 140 days after planting), (ii) storage temperatures (0, 5, 20oC and room temperature) and (iii) types of package (mesh bag, polyethylene and carton) to the qualities of garlic bulbs (growing at Van Hai Ward, Phan Rang - Thap Cham City, Ninh Thuan Province). The research results showed that the proper harvesting time of garlic bulbs in between 130 to 135 days (after planting), garlic bulbs had firm structure and low respiration rate. During the period of maturity, garlic qualities had significant changes. Garlic bulbs in mesh bag at 0oC maintained good quality for six months.

Every year, anthracnose is the main reason causing much damage on chilli plant (Capsicum frutescens). Following the trend of organic agriculture, the method of control anthracnose by Trichoderma is gaining much concerns from researchers. The isolation from diseased plants showed that Colletotrichum truncatum and Colletotrichum acutatum were the causes of anthracnose on chilli plants in Binh Duong province. From vegetable planting areas in Binh Duong, three strains of Trichoderma among 16 isolates strains (T. koningii T2.2, T. koningii T4 and T. koningii T5.1) had the highest ability to antagonize Colletotrichum spp. Also when applying the sporiferous preparation from isolated Trichoderma to chilli plant fields, it helped decrease 58.4 percent of the anthracnose on chilli fruits as compared to control fungicides. Results of this study indicated the possibility of applying Trichoderma spore preparation for treating anthracnose on chilli plants.

A aromatic traditional rice variety “Nang Thom” mainly planted in Ben Luc district, Long An province. Flowering stage was affected by photoperiod due to high pressure discharge lamps along the Ho Chi Minh city – Trung Luong highway. Solving this problem, a set of 10 new aromatic rice varieties were tested. This experiment was carried out in three crop seasons during 2012 to 2014 based on the Tests for Value of Cultivation and Use of Rice Varieties (10 TCN 558-2002). Results showed that two elite breeding lines TLA1 and TLA4 performed well, the yield ranged from 5.80 to 6.50 ton/ha, amylose content less than 20%, protein content >7% and the lines showed fairly good tolerance to insects and diseases.

The study was carried out to determine the optimum concentrations of plant growth regulators (BA and IBA) for shoot establishment from cotyledonary explants of three species of Momordica charantia L. in vitro. Three experiments were included. The first experiment was shoot regeneration from cotynedonary sections. The second experiment was shoot proliferation and the third experiment was rooting. Results showed that: (1) MS medium supplemented with BA 1,0 mg/L and the variety Jupiter 25 were effective for shoot regeneration; (2) MS medium supplemented with BA 0,2 mg/L was effective for the rapid proliferation of shoots in vitro; and (3) The MS medium containing IBA 1,0 mg/L and 2 g/L activated charcoal was favorable for rooting of Jupiter 25 regenerated shoots.

The present study aimed to evaluate the current farming systems and to propose orientation for agricultural land use planning in the Ba Tri district, Ben Tre province. The study applied household interviews, physical land evaluation (FAO, 1976 & 2007) and a mathematical simulation for optimizing land use planning. The results of land evaluation showed that there were three zones which adapted to five land use types, including: triple rice cropping, cash crops, coconut, shrimp, and salt production. The study proposed the land use planning with two major goals (i.e. the optimal income and maximised agricultural production). Five land use types were proposed such as: (1) Triple rice cropping and coconut for zone I with 12,091 ha, (2) Triple rice cropping and cash crops for zone II with 4,475 ha, (3) Cash crops for zone III with 4,983 ha, (4) Triple rice for zone IV with 1,572 ha and (5) Cash crops and coconut for zone V with 507 ha. Intensive shrimp production was proposed for zone VI with 5 ha and intensive shrimp and salt production was proposed for zone VII with 2,143 ha. The study results would help the local government to make the appropriate solutions for agricultural land use planning in the future. In addition, to make appropriate solutions local government needs to support famers with micro-credit and new technologies for local famers to increase agricultural production efficiency.

Salt stress affects the growth, yield and quality of soybean. Mutagenesis through irritation method with gamma ray in combination with in vitro selection on the medium supplemented with NaCl was carried out on the soybean cultivar MTD 760-4 to obtain salt-tolerant callus lines. Results showed that, in salt concentration of 2.5 g/L, most callus grew normally. Salt tolerance to 5 g/L was achieved by culturing non-irradiated and irradiated callus at doses from 5-40 Gy on selection medium with 5 g/L of NaCl  after four times of selection. Callus tolerated salinity to dose of 7.5 g/L when selected at irradiated dose of 5 Gy. Proline content was accumulated highly in salt tolerant callus lines on media containing NaCl concentrations of  5 and 7.5 g/L.

Study on the use of bacteriophage in control of grain rot disease on rice caused by bacterium Burkholderia glumae was conducted in vitro and nethouse conditions. Under in vitro conditions, evaluation of the lytic ability of six bacteriophages i.e. ФHG17, ФVL30, ФVL34, ФVL39, ФAG58 and ФAG60 to host bacterium Burkholderia glumae isolate CT4 revealed that two bacteriophages ФHG17 and ФVL34 expressed higher diameter plaques compared to others. Under nethouse conditions, all six bacteriophages showed effect in reduction of grain rot by spraying a 108 pfu/ml bacteriophage suspension two hour prior pathogen inoculation. The bacteriophage ФVL34 showed highest stability effect in reduction of disease in terms of lower percentage of grain infection and disease scales combined with higher yield compared to the control treatment. Phages ФVL39 and ФAG58 aslo gave good effect in reduction of disease. Disease prevention effect involves to the multiplication of bacteriophages on plant surface after application.

Purpose of the study was to evaluate the effects of calcium chloride as foliar spraying on the fruit cracking phenomena, yield and quality of Rongrien rambutan in the Nhon Ai ward – Phong Dien district – Can Tho city, 2015 season on the five–year–old trees. The experiment was carried out in Randomized Complete Block design with five treatments of calcium chloride (control; 0,5; 1,0; 2,0; and 4,0%), and ten replications, each replication of one tree. The amounts of inorganic fertilizer applied on all treatments were the same. Fertilizers were supplied for trees in 4 times. The first time was 0.32 kg.tree-1 N – 0.23 kg.tree-1 P2O5 after harvesting, the second time was 0.1 kg.tree-1 N – 0.1 kg.tree-1 P2O5 – 0.075 kg.tree-1 K2O 1 month before flowering, the third time was 0.1 kg.tree-1 N – 0.1 kg.tree-1 P2O5 – 0.075 kg.tree-1 K2O at fruit set, and the final was 0.12 kg.tree-1 K2O after fruit set. Results showed that spraying with CaCl2 had an effect on the fruit cracking phenomena through increased total Ca2+ content and peel thickness of fruits. Spraying with 2 – 4,0% CaCl2 at 8 weeks after bloom (4 times, at fifteen–day intervals) reduced the ratio of fruit cracking 1.7 – 2.2 folds, and ion leakage decline 1.62 - 1.73 folds in comparison to the control. Spraying with CaCl2 4.0%reduced yield and oBrix  comparison to the control.

Phytophthora causing root rot and stem canker diseases is the important pest of avocado (Persea americana Miller) worldwide and is the limiting factor for production in many regions. The study aimed to identify the causal agent of root rot and canker of avocado in planting areas of the southeast Vietnam. A survey on the disease occurrence on avocado in provinces of Ba Ria Vung Tau and Dong Nai of the southeastern Vietnam was conducted in 2015. 980 trees of commercial orchards were examined and 48 ones showed symptoms of root rot and stem canker with the mean incidence of 4.90%. Infected trees were consisted of both local and introduced commercial varieties. 48 samples, including of 33 feeder root and 15 trunk tissue samples, were collected and isolated on BNPRAH selective medium. A Phytophthora species, consistently isolated from symptomatic roots and trunk cankers, was identified as Phytophthora cinnamomi Rands, using morphological study and infestation tests to fulfill Koch’s postulates, and DNA analysis. Avocado production has been rapidly expanded during the past 5 years in the country and avocado is presently a good profitable crop of local growers. Root rot and stem canker could become a primary threat to sustainable development of avocado industry in Vietnam.

This study was carried out to evaluate the growth and development of shoot clusters of tuberose (Polianthes tuberosa L.) in vitro irradiated by 60Co gamma doses: 0 (control treatment); 5; 15; 25; 40 and 60 Gy. Results showed that 60Co gamma doses had effects on the growth and development of shoot height, shoot number and leaf number. These growth parameters were significantly decreased by increasing the irradiation dose. Except for 5 Gy dose, most of irradiation doses caused abnormal structures of in vitro shoot clusters. These indicated that there will be more phenotypic variations appearing in the field. LD50 value obtained at dose 21,88 ± 3,52 Gy.

This study evaluated the development of Bacillus amyloliquefaciens in high salinity conditions and effects of adding this bacteria strain into the culture medium of Artemia franciscana. In the first experiment, B. amyloliquefaciens was inoculated at a density of 106 CFU/mL in different salinities of 15‰ (control treatment), 80‰, 85‰, 90‰, 95‰ and 100‰. After 10 days, the result showed that B. amyloliquefaciens could be able to grow and develop at the salinity as high as 90‰ (3.02 ±0.01 log CFU/mL). The second experiment determined the ability of B. amyloliquefaciens to improve environmental factors and bottom sediment in Artemia culture condition at the salinity of  90‰, in the presence or absence of muddy sediment. Artemia were cultured at the density of 100 ind./L and were fed with shrimp feed (Number 0 nursing feed). After 15 days, the survival rate (74.8%) and the mating rate (83.3%) in treatment supplemented with B. amyloliquefaciens, and without muddy sediment were statistically different from those treatments without bacteria supplementation. In the treatment with B. amyloliquefaciens and muddy sediment, Artemia reached higher length (8.7mm) and higher fecundity compared to others (p

This study purpose was to find out the suitable light intensity range for Biofloc formation, survival rate and growth rate for nursing of white leg shrimp (Litopenaeus vannamei) postlarvae. The experiment included 3 treatments of different light intensities of (1) not cover shading net (control treatment), (2) cover with 1 layer of shading net, (3) cover with 3 layers of shading net. Composite tanks of 500 L containing 250 L of brackish water (15ppt) were used. White leg shrimp (PL15) were stocked at 2000 inds/m3 with the weight of 0.03 g/PL15 in strong aeration. Wheat flour and soya bean meal were used at C/N ratio of 15:1. After 6 weeks of experiment, nursing of white leg shirmp in Biofloc system with different light intensities showed strong effects on biofloc formation, growth performances and survival of shrimp. Particularly, total length and weight of shrimp were highest in the treatment 2 (5.35 cm and 1.4 g, respectively) and lowest in the control treatment (4.5 cm and 0.85g). In addition, the highest survival rate (58.07 %) and highest yield (1,161 shrimp/m3)was also found in the treatment 2. The results shown that treatment cover with 1 net layer with appropriate light intensity of 43-308 Lux gave the best results in water quality parameters, growth and survival of shrimp.

Improving combinated gillnet and control combinated gillnet were used to test fishing effort in the Tonkin Gulf with 28 fishing operations in Northeast monsoon and 17 fishing operations in Southwest monsoon. The results show that production of improvement net and control net is 555.6 kg and 1,197.4 kg, respectively. Species composition  were catched of improvement net the same as control net; main species is spanish mackerel, makes up more than 57% of total production. Mean catch-per-unit-effort of improvement net is 1.96±0.23 kg/10,000m2 and being higher than control net - (1.54±0.12 kg/10,000m2) . Mean catch-per-unit-effort for spanish makerel of improvement net (1.74±0.24 kg/10,000m2) is also higher than control net (1.45±0.13 kg/10,000m2).

The study on the fishing activities of inshore and offshore single trawler was conducted from August to December 2015 in Bac Lieu province. The results showed that the number of inshore single trawler in Bac Lieu province were 168 fishing boats (12.8%) and the offshore trawler was 215 fishing boats (16.42%). The inshore trawlers were used for boat with engines of 57.6 HP in average and the offshore trawlers were used for boat with engines of 249 HP in average. The inshore and offshore trawlers can operate year-round. The average fishing productions of the inshore and offshore trawlers were 104 tons/boat and 346 tons/boat per year, in which trash fish accounted for 42.6% of inshore trawlers and 43.67% of the single trawler offshore. The average gross revenues and net return were 145 and 68.2 million VND/trip, respectively and benefit ratio was 104% of inshore trawlers. The average gross revenues and net return were 1,228 and 539 million VND/trip, respectively and benefit cost ratio was 65% of the offshore trawlers.