Vol. 14 No. 6 (2016)

This experiment was conducted to evaluate the effect ofnitrogen ratesand plant densities on physiological and yield characteristics of waxy maize cv. HUA518using two-factorial design. Nitrogen rates and plant densities did not clearly affect plant height, growth durations and ear height, except the case withoutnitrogen application. The posiste effect ofnitrogen ratesapplied and plant density, however, on leaf area index (LAI) and dry matter accumulation was apparent. These characteristics were closely correlated with yield atmilking stage in all nitrogen treatmentsduring both 2013 autumn -winter and 2014 spring seasons. Yield was affected most by density and fertilizer treatments.The nitrogen rate of 190 kg N/haplus90 kg P2O5and70 kg K2O/ha and the density at 57,000 -61,000 plants/ha gave the highest yield (yield 11-11.8 tons of fresh waxy maize/ha).

Longan gall mite, Eriophyes dimocarpi,is a vector of longan witches’ broom disease (LWBD). The causal agent of thedisease is very intricate and difficult to control. Management of this disease includes avarietal selection andvector control. The study onmanagement of longan gall mite and LWBD wásconducted at SOFRI and longangrowing areas in the Mekong Deltafrom April 2013 to November 2014. The results showed that Tieu da bo variety of longan was highlysusceptiblewhileEdor, Vung Tau and Thach kiet varieties were susceptibleandXuong com trang, Cui, Long Hung Yen varietiesand NL1-19 hybrid were moderately susceptible. Giong, Sai Gon and NL1-23 hybrid were moderately resistant. Meanwhile, Xuong com vang, Long and Supervarieties were highly resistant to thedisease after 11 months treatment. NL1-23 hybrid was moderately susceptible to this disease after 12months planting.

Analysis of physiological characteristicsof peannut varieties with high and low yield was done to identify criteria that contribute yield, quality, and toleranceto unfavourable environmental conditions. The experiment was conducted in 2013, 2014 and 2015 spring seasonsin Trieu Son, Thanh Hoa province. According to the yield, 10 peannut varieties weredivided into 3 groups: highyieldingvarieties: L26andTB25;low yielding varieties: lac lyandL12, sen lai;and the mediumyieldingvarieties: L18, L08, L14, L19andL23. The high-yielding varieties exhibithigher photosyntheticintensity(26,8mol/m2/s), dry matter accumulation (24,26g), transpiration rate (11,85mmol/m2/s), stomatal conductance(0,64mmol/m2/s), leaf area(16,22dm2), andchlorophyll content(1,76mg/g) atflowering stage.

The objectives of this study were to find the optimalsperm dilutionandgentamycin concentration forWaigieu seaperch,Psammoperca waigiensis,chilled sperm preservation throughout the spawning season. The semen werediluted at 1:1, 1:3, 1:5 and1:7 in artificial seminal plasma. Gentamycin was added at concentration of 100, 200 and300 ppm. Semen dilution at1:3and addition of 200ppm gentamycin with sperm collected at the beginning spawning season and the middle spawning season and dilution ratio of 1:5 with300ppm gentamycin with sepermcollected at end spawning seasonyielded highest sperm motility.

The use ofantibioticsfor treating fish diseases has severaladvantagesbutraises theconcerns about antibiotic residues in fisheryproductsand increasesantibiotic resistance of pathogenic bacteriaas well. Herbs have been increasingly demonstrated their important role in the pharmaceutical industry as a biosafety solution, an alternative to synthetic chemical drugs. The present study aimed to examine the efficiencyof leaf extraction fromPiper betleby five different solvents (distilled water,methanol 80%, ethanol 96%, n-hexan andaceton 100%), and evaluate the anti-bacterial effects of the extract on Aeromonasspp. and Streptococcus agalactiaewhich cause hemorrhagic disease in tilapia. The results showed that the extractionefficiency varied from 4,00% (n-hexan solvent) to 19,67% (ethanol 96% solvent). At the concentration of 100 mg/ml, all these extracts showed good antibacterial activity against Aeromonasspp. and Streptococcus agalactiae.For Aeromonasspp., the inhibition zone variedfrom 15,00 mm (distilled water solvent - DW) to 28,00 mm (ethanol 96% solvent). The inhibition zones of Streptococcus agalactiaewere variedfrom 17,67 mm (DW solvent) to 31,67 mm (ethanol 96% solvent). The ethanol-extract solution showed highestanti-bacterial effect. This extract remained the anti-bacterial activity to Aeromonasspp.and Streptococcus agalactiaeat concentration 0,39mg/ml and 0,78 mg/ml,respectively.

This study was conducted to determine some clinical parameters and pathological charactesistics of Tre chicken infected with coccidiosis in Thua Thien Hue. 978 fecal samples of chicken aged 1-42 days were collected and tested for oocyst presence by flotation method and some clinical parameters were determined. Concurrently, all died chickens caused by coccidiosis were slaughtered to collect the samples for determination of both macroscopic and microscopic pathological changes. Results showed that the average coccidian infection of three communes was 50,92%. Tre chickens were infected with coccidia from a very early stage and oocysts appeared in excrement in the period of 8-14 days of age. The rate and intensity of coccus infection increased and reached the peak when chickens aged of approximately 15 - 35 days, then reduced gradually. Infected chickens showed droop, inactiveness, watery diarrhea with mucus, and bloody or creamy exudate feces. The main macroscopic lesions of infected chickens showed hemorrhagic and huge necrosis in intestine and caecum, distended caecum and eroded mucosal layer. The microscopic lesions consisted of severe hemorrhage, necrosis, degeneration of epithelial cells, and inflammatory infiltrations in caecum. On the other hand, pathogenic characteristics also could be observed in ileum and rectum. The different stages of coccidia were also observed in the epithelial cells.

Wild pigs are increasingly raised in Vietnam. However, documents related to the common reproductive diseases are rare. The present study aimed to investigate common diseases, determine the efficiency of preliminary treatment of metritis, and analyse the effects of postpartum metritis on the length of the interval from parturition to post-weaning estrus and post-weaning conception rate in wild sows. Overall, 102 wild sows from 5 farms were monitored. Results showed that common diseases in wild sows are metritis, mastitis, agalactiae and dystocia. Preliminary treatment of metritis with Lutalyse injection, Lugol and Neomycin infusion conferred very high cure rate. Wild sows with postpartum metritis have a significantly longer interval from parturition to post-weaning estrus, while their post-weaning conception rate is significantly lower compared with healthy sows. The present study showed that postpartum metritis is a common disease in wild sows, and it may hamper their reproductive performance.

Pyrethroid pesticide toxicity testing onfreshwater snail (Angulyagra polyzonata)wasdone in laboratory scale by artificial exposure to Cypermethrin and Deltamethrin for96 hours period. The results showedthat Angulyagra polyzonatawas more sensitive toDeltamethrin than Cypermethrin.The recovery of freshwater snails was descending whenexposed to pyrethroids for 48 hours and then released into water within 48 hours. Bioaccumulation fator (BCF) with Cypermethrin was0.88and26.29 with exposure time of one day and one month, respectively.

This study was carried out to assess and determine limitations and shortcomings in the transfer of land use rights for households and individuals, thereby propose solutions to enhance the efficiency of land use right transfer in in Pho Yen district. The results showed that total transfer of land use right was 7.148 cases, including 4.082 in residential land and 3,120 in agricultural land. The transfer of land use rights is enforced by the land law, but there existed some shortcomings such as transfer status without registering with state agencies, lower transfer contract price compared with transaction price, dificulty in the search for market information,… The solutions to solve the above shortcomings are regular inspecting and supervising the transfer of land use rights, enforcing strong sanctions on use right transfers not approved by state agencies, building database for real estate market, advocating land law to the people, training to enhance knowledge and supplementing professional staff of land use right transfer.

Một số dẫn xuất của coumarin có hoạt tính sinh học cao, như tác dụng chống co thắt, làm giãn nở động mạch vành, chống đông máu, chữa bệnh vẩy nến, kháng khuẩn, chống nấm, chống viêm,... một số có tác dụng ức chế HIV.Trong nghiên cứu này chúng tôi thực hiện việc tổng hợp một số dẫn xuất coumarin theo phương pháp không dung môi trong lò vi sóng bằng phản ứng cộng hợp nucleophin với các amin khác nhau, cho hiệu suất đạt từ 55-70%. Các sản phẩm coumarin cũng đã được khảo sát hoạt tính sinh học, kết quả cho thấy các sản phẩm tổng hợp được đều có tính kháng khuẩn, chống nấm cao.

Hemerocallis fulva is considered as a crop with high ornamental and medicinal value. In this study, we initially determined the basic parameters of the in vitro multiplication for H. fulva, including appropriate in vitro initiation medium, culture medium, and rooting and hardening media for H. fulva. The results showed that the optimal medium for in vitro initiation culture was MS + 1 mg/L BA + 1 mg/L -NAA. The suitable medium for in vitro shoot multiplication was MS + 1 mg/L BA + 1 mg/L IAA; The rooting medium was MS supplemented with 0.5 mg/L -NAA; Highest efficiency for hardening of Hemerocallis fulva in vitro-derived plantlets in green house was achieved with moist alluvial soil.

This paper presents the results on induction of adventitious roots of Morinda officinalis How and effect of some chemical factors on adventitious root growth. Stem and leaf explants were cultured on MS medium supplemented with -NAA, IAA and IBA at five concentrations (0.1-1.0 mg/l) to regenerate adventitious roots. Among the auxins, -NAA showed the highest adventitious root formation for stem explants, followed by IAA and IBA. The maximum percentage of stem explants induced root (100%) was obtained when cultured on MS medium supplemented with 0.75 mg/l -NAA after 4 weeks of culture. However, adventitious root induction was not observed in leaf explants cultured on MS + 0.75 mg/l -NAA. Of the two tested media, B5 medium sustained better root growth than MS medium. -NAA, IAA and IBA had positive effect on adventititous root growth and development. After 12 weeks, the highest adventitious root biomass (1.264 g) was obtained on B5 medium supplemented with 1.0 mg/l -NAA.

Physical model built for the vertical cone-shaped screw mixer consists of two physical models to determine the capacity and productivity of the vertical cone-shaped screw mixer. Based on the physical models we built vertical cone-shaped screw mixers identical with that of optimum parameters. Research process for the different machine models to raise productivity in calculating, design, manufacturing can be shortened but vertical cone-shaped screw mixers with optimal work fitting to the different power and productivity could be achieved.

Stemming from the practical needs for a system to support users in searching information about animal diseases quickly, accurately, and completely based on symptoms and lesions, we have collected, synthesized and standardized data and programed functions for online animal diseases lookup system. Introduction of the system at http://www.benhvatnuoi.vnprovides an optimal database management tool which supports users in searching animal disease information accurately and completely. This is also the first online animal diseases lookup system in Vietnam for pigs and chickens.

At present,  effective lighting and energy saving  are of great concern by society. There are many methods to save electrical energy. This study assessed the current state of the lighting system in the class rooms and the auditorium of the Viet Nam National University of Agriculture and proposed solutions for efficient lighting system, saving energy and selection of optimal scheme.

Số lượng các tổ chức giáo dục và các trường đại học ở Việt Nam hiện nay đang tăng lên buộc các trường đại học nói chung và Học viện Nông nghiệp Việt Nam (VNUA) nói riêng phải cố gắng để thu hút sinh viên bằng cách cung cấp cho họ các dịch vụ tốt nhất, mang lại cho họ sự hài lòng cao nhất có thể. Bài viết nghiên cứu sự hài lòng của sinh viên trong khoa Kế toán và Quản trị Kinh doanh (FABM) tại VNUA về chất lượng dịch vụ đại học. Phiếu điều tra được sử dụng để thu thập dữ liệu từ 102 sinh viên hiện tại của khoa FABM. Kết quả cho thấy rằng chất lượng của các nhóm dịch vụ chính tại VNUA được đánh giá từ mức độ trung bình đến mức độ tốt. Một nửa số sinh viên được phỏng vấn hài lòng về dịch vụ với các chỉ số hài lòng trung bình là 3.36. Sự sẵn có của các dịch vụ hiện tại đủ để đáp ứng và thỏa mãn nhu cầu của sinh viên ngành Kế toán và sinh viên các năm thứ nhất và năm thứ hai trong khi các sinh viên trong ngành Quản trị Kinh doanh và sinh viên năm thứ tư có vẻ chưa hoàn toàn hài lòng. Nghiên cứu này đề xuất một số gợi ý để cải thiện và nâng cao sự hài lòng của sinh viên bằng cách đầu tư vào cơ sở hạ tầng và cơ sở vật chất, cải thiện mạng internet nội bộ, nâng cao trình độ chuyên môn cho nhân viên hành chính.