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The Mangrove Flora in Thach Han and Ben Hai Rivers, Quang Tri Province

Nguyen Kim Thoa, Do Anh Duy, Bui Minh Tuan, Tran Van Huong, Phung Van Gioi

Received: 03-03-2021 / Accepted: 23-04-2021
The study was conducted in December 2019 and August 2020 to assess the status of mangrove flora distribution in the Thach Han and Ben Hai Rivers, Quang Tri Province. As a result, 16 species belonging to 13 families, 3 classes of 2 phyla (ferns and angiosperm) were recorded. The mangrove apple, Sonneratia caseolaris is the main species distributing in these areas, accounting for over 60% of the distribution. In Ben Hai, the majority of the area was occupied by natural mangrove apples that formed narrow strips along the river. In Thach Han, mangrove apples which were grown in the swampy tidal areas and aquaculture ponds were collected by the State for forest development. The distribution area of mangrove in Thach Han River was larger and higher indensitycompared with Ben Hai River. The average coverage rate was 84.0%. The average density was 72.4 individuals/100 m2. The results in this study have provided a general picture of the current status of mangrove distribution in these two areas.
Effect of Nanocurcumin on Growth Performance, Carcass Yield, Meat Quality and Hematological Parameters of Broiler Chicken Ross 308

Bui Huy Doanh, Dinh Thi Yen, Pham Thi Thu Ha, Nguyen Thi Chau Giang, Luu Hai Long, Luu Hai Lan, Luu Hai Minh, Dang Thai Hai, Pham Kim Dang

Received: 17-04-2023 / Accepted: 29-08-2023
This study aimed to evaluate the effect of dietary nanocurcumin on growth performance, carcass yield, meat quality and blood physiological parameters of Ross 308 chicken. A total of 120 one-day-old Ross 308 chickens were randomly allocated into two treatments: (1) control group fed basal diet and nanocurcumin group feda basal diet supplemented with 200 mg nanocurcumin per kg. Each group was replicated three times. The results showed that supplemntation with nanocurcumin in the diet did not affect the survival rate, daily gain, body weight, daily intake, carcass yield and meat quality (P >0.05). The feed conversion ratio in nanocurcumin group (1.32) was lower than in the control group (1.36) (P <0.05). Proportions of abdominal fat, the weight of the liver, heart and spleen were not different between control and nanocurcumin groups (P >0.05). Dripp loss, pH and meat tenderness did not significantly different, except b* values of breast (P <0.05). Hematological parameters in nanocurcumin group were higher than those in control group (P <0.05), except lymphocytes proportion.
Research on Complete Techniques for Commercial Cultivation ofSlender Red Seaweed (Gracilaria tenuistipitata)

Do Anh Duy, Bui Thi Thu Hien, Nguyen Thanh Binh, Bui Minh Tuan, Nguyen Van Sau

Received: 24-10-2023 / Accepted: 23-05-2024
The aim of this study was to advance grow-out cultivation techniques of slender red seaweed (Gracilaria tenuistipitata)in experimental conditions, serving as basis for experimental farming on a commercial scale, contributing to improving productivity and ensuring the quality of raw material seaweed. Four experiments were conducted: (1) culture density, (2) fertiliser doses, (3) depth for cultivation and (4) biomass of seaweed seedlings left after harvesting. Each experiment was repeated three times from May to December 2022 in Thai Thuy District, Thai Binh Province. Research results show that the optiml initial density of seaweed seedling was 600 ± 50 g/m2; basal fertilizer with a dosage of 0.2 kg/m2and inorganic fertilizer as nutrient supplement with a dosage of 0.02 kg/m2were most appropriate in commercial slender red seaweed farming; the depth for cultivation of Gracilaria tenuistipitataof 60 ± 5cm was best for control of the algae fouling; and the appropriate biomass of algae seedlings left after harvesting was 550 ± 50 g/m2.
The Research Result of Development Stages of Scaly giant clam’s Gonad (Tridacna squamosaLamarck, 1819) by Histology Method

Do Anh Duy, Nguyen Quang Hung, Tran Van Huong, Dong Thi Dung, Nguyen Thi Thu Ha

Received: 07-06-2012 / Accepted: 18-08-2012
The report presents research results of the development stages of scaly giant clam’s (Tridacna squamosa Lamarck, 1819) gonad in 8 Vietnam islands from 2010 to 2011. The scaly giant clam samples were collected in coral reef (from March to July) and from the divers in Nha Trang Bay and adjacent areas (in months). Histological method was employed to analyze the development stages of gonad. The research results showed that scaly giant clam is a hermaphroditic species. The individuals with the shell length under 18-20cm exhibit maleness character while in individuals with the shell length above 18-20cm the gonad differentiate into spermary and ovary. The development of scaly giant clam’s gonad experiences 6 stages (from stage 0 to stage V). Among them, stage III, the largest size are in the eggs and sperms. The egg cells are round or elliptic in shape and arranged with each other in the ovaries. Diameter of the eggs is measured at 90-110μm. The spermary contains a large quantity of mature sperms; the sperm head size is about 3μm. The research results are useful for identifying each stage of the development of scaly giant clam’s gonad and breeding season through the level of the gonad maturity.
Effectof Stocking Density on Growth Rate and Survival of White Leg Shrimp, Litopenaeus Vannamei,Raisedon Indoor Composite Tanks

Nguyen Phuong Toan, Vu Van Sang, Nguyen Viet Vuong, Nguyen Quang Tuat, Dang Thi Diu, Doan Thi Nhinh, Tran The Muu, Vu Van In

Received: 18-02-2013 / Accepted: 20-04-2013
The effect of stocking density of white leg shrimp SPF (Litopenaeus vannamei) was carried out at different density of 40, 60 and 80 PL15/m2 for 75 days. Each treatment was replicated three times in 4m2 indoor composite tank system and feeding ratio of 10-15% body weight with CP pellets containing 38% crude protein and four times a day. During the experiment, water temperature varied between 28 and 31ºC, whereas salinity ranged from 20-24‰ in biosecurity condition. Water in the culture tanks was renewed 50% weekly. The highest growth rate in weight was found in treatment of 40 heads/m2 (1.54 g/week), followed by 60 heads/m2 (1.47 g/week) but the rate for 30 heads/m2 (1.16 g/week) was lowest. Similarly, the survival rate of shrimp stocking at 40 heads/m2 ranked highest (79.7 ± 2.6%), followed by 60 heads/m2 (78.7 ± 2,9%) and the lowest rate for the 80 heads/m2 (70,3 ± 3,3%; P<0.05). Nevertheless, there was no significant difference in the survival rate between shrimp raised at 40 heads/m2 and 60 heads/m2 (P>0,05). Size variation (CV) for 40 heads/m2 (727 ± 1.52%) and 60 heads/m2 (8.22 ± 2.5%) were considerably lower than that for 80 heads/m2 (12.9 ±2.7%; P<0.05). However, there was no considerable disparity in feed conversion rate among the three treatments (P>0,05). All shrimp sample tissues were found negative for WSSV, YHV, TSV, MBV and IHHNV.
Characteristics of Shrimp Resources in the Coastal Waters of Hai Phong - Quang Ninh

Vo Trong Thang, Nguyen Van Giang

Received: 07-07-2022 / Accepted: 27-01-2023
This study was conducted to identify the current status shrimp resources in the coastal of Hai Phong-Quang Ninh. From 2013-2019, a total of 88 hauls were collected during four surveys representative for the Northeast and Southwest monsoon seasons by a single-shrimp trawler. The survey was conducted applying the fixed sampling stations. Research results identified 53 species of shrimp in 23 genera belonging to 10 families, of which the Penaeidae family was most abundant with 29 species. Research results updated and supplemented 25 shrimp species, including 12 white shrimps and eight mantis shrimps, and identified 25 commercial shrimp species in the study area. Shrimps contributed to 18.31% of the total catch, their proportion in the coastal waters was 30.34% higher than in the inshore (12.92%). The average shrimp yield in the Southwest monsoon season was higher than in the Northeast, with an average was 7.31 kg/h. The average biomass density in the study area was 303.56 kg/km2, and the stock of shrimp was estimated at 2,494 tons in the Northeast monsoon season and 5,116 tons in the Southwest monsoon season. The present study provided the information for protecting and sustainably exploiting shrimp resources in the research area.
Variation of Marine Fishery Resources in the Gulf of Tonkin from 2000 to 2015

Mai Cong Nhuan, Nguyen Khac Bat, Vu Viet Ha

Received: 25-05-2018 / Accepted: 11-12-2018
A survey was conducted to assess variation of marine fishery resources in the Gulf of Tonkin from 2000 to 2015. The swept area method for demersal and near demersal fish groups and hydroacoustics method for pelagic fish group were used. The survey data on fishery resources conducted annually in the Gulf of Tonkin during 2000-2015 period revealed about 568 marine fishery species/groups belonging to 321 genera, 145 families, including demersal fishes (197 species), pelagic fishes (70 species), crustaceans (47 species) and squids (30 species). In 2000-2005 period, the total standing biomass (TSB) was estimated at about 453,000 tones and the maximum sustainable fishing yield (MSY) about 225,000 tones. From 2010 to 2015, the TSB was estimated about 752,000 tones and 719,000 tones, respectively, for the NE and SW monsoon seasons, and the estimated MSY was about 350,000 tones. Noticeably, the pelagic fishes accounted for about 70-80% of the MSY values while the figure for the demersal fishes was only about 20% in both periods.
Effect of Stocking Density on Growth and Survival Rate of Mouse Grouper (Cromileptes altivelis) Larvae FromFry to Fingerling Stage

Vu Van Sang, Tran The Muu, Le Xan, Pham Thi Lam Hong, TranThi Nguyet Minh, Nguyen Van Phong, Vu Van In

Received: 15-12-2013 / Accepted: 26-02-2014
The study was carried out to identify the most suitable stocking density for mouse grouper larvae (Cromileptes altivelis)from fry to fingerling stage. The larvae were reared at the densities of 10,20 and 30 individuals/l. Lower stocking densities, at 10 and 20 individuals/l weremore favorable forspecific growth rate (0.063 and 0.0625%/day), final total length (34.45 and 33.33mm)and survival rate (6.45 and 6.30%)(P<0.05). Results showed that the most appropriate density for rearing the mouse grouper from fry to fingerling stage is 20 individuals/l to optimize the growth, survival rate and economic efficiency.
Some Issues on Livelihoods of Fishermen in Coastal Area of Hai Phong City

Nguyen Van Cuong, Pham Van Dinh, Bui Thi Hoa

Received: 29-12-2014 / Accepted: 14-04-2015
Fishery economy is one of the key economic sectors of Hai Phong city that contributes about over 2.3% share to the city’s GDP and provides about 2,000 employment positions per year on average in the 2005-2012 period. In 2012, seafood exports from Haiphong reached USD 36.5 million, a positive contribution to the city’s overall economic growth. However, most fishermen in the coastal areas of Hai Phong city are still considered as a difficult and socially disadvantaged target group. The issues such as the depletion of marine resources, especially coastal resources, Eastsea conflicts, competition for fishing area and others have a great impact on fishermen’s livelihoods. Although there are many guidelines and policies on the development of marine fishery and support for fishermen, the results are still limited. Based on the theory of livelihood, some issues related to the life, and the employment of fishermen in Haiphong, this paper focused on analysis and evaluation to clarify the status of fishermen’s livelihood resources (human, natural, physical, social and financial resources), the impact of vulnerable environment to fishermen’s livelihoods, and the implementation of fishery development and fishermen support policies of Hai Phong City in the past period, thereby recommending solutions to help fishermen improve their livelihoods, generate employment stability, increase their incomes and minimize risks and damages caused by the vulnerable environment.
Current Situation of E-Invoicing in Small and Medium-sized Enterprises: Case Study in Hai Duong Province

Tran Thi Thuong, Phan Le Trang, Nguyen Thi Hai Binh

Received: 15-03-2023 / Accepted: 20-11-2023
This study described the current e-invoice use of small and medium-sized enterprises in Hai Duong province. Research methods include descriptive statistics and the Likert scale. Research results show that 86.3% of small and medium-sized enterprises surveyed have applied e-invoicing. The core reason was the compulsory application of E-Invoice from the Ministry of Finance. However, in using E-Invoice, some errors have arisen such as (1) Error when registering to use E-Invoice and (2) Error when issuing e-invoice, issuing agency code tax. Therefore, to increase the efficiency of using e-invoices, some recommendations were proposed for small and medium-sized enterprises, organizations providing e-invoice services, and the Hai Duong Provincial Tax Department to promote the use of e-invoices.
Effects of Plant Growth Regulators on in vitroPropagation of Kaempferia galanga L.

Dinh Truong Son, Chu Dinh Thuc, Tran Van Hai, Pham Hong Hien, Pham Thi Thu Hang, Nguyen Thanh Hai, Nguyen Thi Lam Hai, Dang Thi Thanh Tam

Received: 08-03-2021 / Accepted: 16-06-2021
The study aims to develop a simple protocol for in vitro regeneration of Kaempferia galanga L., a local medicinal plant in Vietnam. The rhizome buds (2-3cm) were collected as initial explants and surface sterilized with 0.1% HgCl2for 10m. Initial in vitro shoots were cultured in MS medium supplement with different plant regulatorsincluding BA, Kinetin, NAA and IAA. The combination of 2 mg/l BA and 0.5 mg/l NAA induced the highest shoot multiplication with a mean of 5.03 shoots per explantafter 4 weeks of culture. In this optimal shoot induction medium, in vitro shoots also induced vigorousshoots and roots after five cycles of multiplication. The proposed medium is an efficient medium for in vitro rapid propagation or conservation of K. galanga L.
Establishment of in vitroPropagation Protocol for Baikal Skullcap (Scutellaria baicalensisGeorgi.)

Dinh Truong Son, Bui Huy Hoang, Nguyen Hai Ninh, Ninh Thi Phip, Pham Ngoc Khanh, Dang Thi Thanh Tam, Nguyen Thi Lam Hai, Nguyen Thanh Hai

Received: 18-05-2020 / Accepted: 28-12-2020
Baikal skullcap (Scutellaria baicalensisGeorgi.),a member of the Lamiaceae familyhas been commonly used in traditionalmedicine. Baikal skullcap (called“Hoang cam” in Vietnamese) was introduced into Vietnam and has been planted in some areasin this country. Due to its naturally slow growth and development, large growing areas have not been developed yet. Presently, the most common method of propagation of Baikal skullcap isusingits seeds. Thisstudywas conducted toestablish a rapid micropropagation protocol that can beappliedfor multiplicationof elite strainsand actively provide the disease-free seedlings. The seeds were sterilized using0.5% Presept solution for 15 min, then placed on a medium containing water, sucrose, and agar for germination. Microshoots were highly induced and multiplied (7.47 ± 0.57 shoots/explant) on MS medium supplemented with 1mg/l BA. The suitable sucrose concentrations for the growth and development of microshoots were 20 g/l or 30 g/l. Allshoots were rootedby 100% by addingMS medium supplemented with 0.8-1.6 mg/l IBA. Therefore, theestablished protocol can be applied forin vitro micropropagationofBaikal skullcap.
Species Composition and Change in Fishery Resources in Mangrove Area of Phu Long, Cat Hai, Hai Phong City

Nguyen Van Quan, Nguyen Thi Huong Lien

Received: 19-03-2014 / Accepted: 30-05-2014
This study aimed to identify the species composition and change in natural fishery resources based on materials collected from two fieldtrips (dry and wet season) carried out in 2011. Additional available data came from several projects implemented during 2003-2011period int the mangrove area of Phu Long commune, Cat Hai district, Hai Phong city. The fishery statistical data have been provided by the Hai Phong Department of Agriculture and Rural development. Based on the specimens collected in the 2011 fieldtrips, 63 species belonged to 42 genera in 25 fish families have been identified. Two current typical fishing practices, trawl fishing and bottom fencing net, yieled in different fish group harvested. Especially, the juvenile/fingerling fishes (body length < 10cm) occupied up to 90% of each harvest/catch. In contrast, only a small quantity of high economic species of adult size (21-30cm and > 30cm) was found in the catch. Rapid decline of natural fishery resources was shown in the trawl fishing ( 85-92%) in the 1990-2011 period and up to 50% of the fishing yield in the botton fencing net. These are clear evidences that coastal resources are under serious threat. It is necessary to increase the legal effectiveness for marine resource protection and socialized conservation towards sustainable management of natural resources.
Performance of Cooperatives in Tien Hai District, Thai Binh Province

Le Thi Thanh Hao, Vu Ngoc Huyen, Nguyen Van Song, Bui Thi Nga, Nguyen Quang Nam

Received: 20-04-2020 / Accepted: 08-09-2020
The study investigated 35 cooperatives and 105 members of cooperatives in Tien Hai district in order to collect the situation and to propose recommendations to improve the results of production and business activities of cooperatives in the district. The study investigated 35 cooperatives and 105 members of cooperatives in Tien Hai district in order to collect information on production and business activities of cooperatives. On the basis of analyzing the current situation, the study has proposed some recommendations to improve the results of production and business activities of cooperatives. The results showed that most of the cooperatives in Tien Hai are operated in many fields with two main business activities, production and service provision. In the period of 2016-2018, the average profit tended to increase but remained at low amounts. The profit was mainly used for reinvestment, without distributing to members. The majority of cooperative members must take the initiative in capital generation and product consumption. The mobilization of capital from the members is minimal. Members are satisfied with participating in the cooperative; the quality and price of products and services provided by the cooperatives are assessed at good levels. However, the role of cooperatives in helping members increase revenue, increase profits and the initiative to seek new ideas to increase the performance is only at a neutral score. In order to improve the performance of cooperatives in the district in the coming time, the authorities, cooperatives and members need to focus on: solving capital difficulties; promoting investment in consumption activities; strengthening linkages between businesses with cooperatives and members; and encouraging the cooperatives and members participate in safe agricultural value chains.
Effects of Fruit Pruning and Wrapping Materials on Fruit Size and Quality of Jujube Fruit (Ziziphusmauritiana Lamk.)Variety 05

Nguyen Thi Phuong, Nguyen Hoang Viet, Vu Thanh Hai, Nguyen Thi Thu Huong, Nguyen Thi Hai Xuan

Received: 17-12-2019 / Accepted: 03-02-2020
The study aimed to evaluate the effects of fruit thinning and fruit wrapping materials on fruit size, fruit quality traits and fruit loss rate due to insects and diseases infecting jujube fruit variety 05. Two independent experiments were conducted on 3-year- old jujube plants, which was designed as a randomized complete block design with four treatments and three replications per treatment. Fruit thinning treatments included removing 10%, 20%, 30% and zero % (control) of the total number of fruits per plant. Fruit wrapping material treatments included nylon bag, sponge bag, oil bag and no-wrapping (control). The results showed that fruit thinning increased fruit size, fruit weight and total soluble solids content (TSS), and decreased total acid content (TA) of the fruit. Out of fruit thinning treatments, thinning 30% of the total fruit number per plant resulted in the highest fruit weight (99.36 g) and TSS (17.2oBrix), and the lowest TA (0.180%), at the same time, the treatment reduced actual fruit yield (37.8 kg/plant) and increased the net revenue (772.000 Vietnam dong/kg). Wrapping fruits by nylon bag and sponge bag increased fruit weight of 25.3% and 17.7% compared to the control treatment, respectively. The sponge bag returned the second rank of fruit yield (44.7 kg/plant) and net revenue (1,001,000 Vietnam dong/plant) and did not affect TSS value (17.02%). The nilon bag decreased TSS (15.69%) but returned the highest fruit yield (47.8 kg/plant) and net revenue (1.258.000 Vietnam dong/plant). Therefore, the application of the wrapping materials into commercial production of jujube, nilon and sponge bags, is potentially economical.
Effect of Nitrogen on Growth and Yield of Quinoa Accessions

Dinh Thai Hoang, Nguyen Tat Canh, Nguyen Viet Long

Received: 29-10-2014 / Accepted: 09-03-2015
This study evaluated growth and yield of two quinoa genotypes in winter-spring and spring-summer growing seasons under different levels of nitrogen fertilizer applied to determine growing season and dressing dose for quinoa production in the Red River Delta, Vietnam. The field experiment was a split-plot design with three replications. The main factor consisted of four nitrogen levels: N1- 0kg N; N2- 30kg N; N3- 60kg N và N4- 90kg N/ha ( winter - spring season) and N1- 30kg N; N2- 60kg N; N3- 90kg N và N4- 120kg N/ha (spring - summer season). The sub-factor consisted of two quinoa genotypes of Chilean origin, Green and Red quinoa. Data were collected for growth duration, plant height, stem diameter, dry matter accumulation, chlorophyll index (SPAD meter), lodging tolerance, pests and diseases, number of panicles/plant, number of grains/panicle, 1000 grain weight and grain yield. Increased nitrogen levels prolonged crop duration in spring - summer season only but increased dry matter accumulation, number of grains/panicle, 1000 grain weight and grain yield of both quinoa varieties in both growing seasons. Application of 90kg N/ha appeared as optimal dose for growth, development and yield of quinoa varieties in both growing seasons. The results showed that winter - spring season was favorable for growth and grain yield in the Red River Delta.
Influence of Intercropping and Fertilizer for Mondo Grass on Weeds, Disease and Insect Pests at Young Tea Garden

Nguyen The Hinh, Nguyen Dinh Vinh, Nguyen Van Tuat

Received: 05-09-2012 / Accepted: 28-11-2012
Intercropping of Mondo grass (Ophiopogon japonicus Wall) into tea garden of cv. Kim Tuyen (1-3 years old) is aimed to increase the land coverage, create the favorable conditions for the tea growth and improve the farmers’ income. The impacts of mondo grass intercropping and seven fertilizing formulae on pest occurrence (diseases, insects and weeds) and plant damages were investigated. The major findings are: (i) 15 weed species were found in tea garden, (ii) Mondo grass intercropping can reduce the biomass of weeds in the tea garden, and (iii) The mondo grass is not the host plant of pests on tea. The intercropping of mondo grass led to changes in solar radiation, soil moisture and land coverage which favor pest occurrence and damage such as increasing the density and damage of Empoasca flaescens Fabr. & E. onukii Mats., Helopelthis theivora Waterh, and Colletotrichum camelliae Marasmius equinis Muler Derk. but reduce the density of Physothrips setiventris Bagn and Oligonychus coffeae Niet. on the tea plants.
Evaluation of Growth, Yield and Pharmaceutical Quality of Some Mugwort (Artemisia vulgaris L.) Accessions in Gia Lam, Ha Noi

Ninh Thi Phip, Nguyen Thi Thanh Hai

Received: 20-09-2015 / Accepted: 18-03-2016
The growth and quality of 10 mugwort accessionswere evaluated in a replicated experiment (RCBD with 3 replications). Harvest wasdone when plants reach a height of 30-35 cm for all accessions. Highest individual plant yield and hectare yield per year were obtained from accessionG6with shorter cut interval and more cuts per year.The accession G6 had higher content of total essential oil (0.37%), which is well suited for useas fresh vegetable or medicinal materials. AccessionsG5, G13 and G14 with high content of total essential oils (0.5%), high total flavonoid content ( >7000 mg/100 g) are suitable for essential oil and flavonoid extraction. Accession G2 with low total essential oil (0.21%) and slightly bitter is good for using as fresh vegetableas supplementalfood.
Factors Affecting Satisfaction of Labours of Hai Duong Province Participating in Labour Export to Japan Market

Tran Nguyen Thi Yen, Phan Le Trang, Phi Thi Diem Hong

Received: 07-06-2021 / Accepted: 09-12-2021
The purpose of the study was to determine the factors influencing the labours’ satisfaction when they participate in the labor export program and make decision to accept or not accept again a new labor export contract. Applying the JDI model and prior researches' results as background, the research identifed the factors relating to labour’s satisfaction with 20 criteria classified into 5 groups, i.e application procedures, training, working conditions, income and specific job position. The survey was conducted on 164 labors in Hai Duong province who had been or being participants of the labor export service to Japan. Results showed that income was the largest impact factor of satisfaction, followed by the job position and working condition.
Species composition of Bivalve Mulluscs (Bivalvia) Recordedin the Coral Reefs Coastal Central Vietnam

Bui Minh Tuan, Hoang Dinh Chieu, Nguyen Kim Thoa

Received: 09-06-2020 / Accepted: 25-11-2020
Research on species composition and distribution of bivalvia in central coastal coral reefs was conducted in 2015-2016, in 6 central coastal areas (Nghi Son, Ky Loi, Son Tra, Ghenh Rang, Tuy An and Vung Ro). The results have identified 50 species, belonging to 16 families, 7 orders in the coastal reef in this area. Four endangered species have been identified in the coastal reef ecoregion (list of the Vietnam Red Book). Sorensen species similarity index in the investigation area ranged from 0.37 to 0.70. The diversity index of Shannon - Wiener ranges from 2.83 (Nghi Son) to 3.31 (Son Tra) ... The results of this study contribute to the diversity of the composition of bivalve mollusks in the reproductive system. Coastal reef status in Vietnam is the basis for planning and protecting this resource against the effects of socio-economic activities in coastal areas.
Influencesof Host Plants on the Biology of Two-Spotted Spider Mite Tetranychus urticaeKoch (Acari: Tetranychidae)

Tran Ngoc Cam, Nguyen Duc Tung

Received: 29-11-2019 / Accepted: 31-01-2020
Tetranychus urticaeKoch (Acari:Tetranychidae) is a dangerous peston manycropsin Vietnam and worldwide. The objective of this study wasto find outthe biological and ecological characteristics of this harmful two-spotted spider miteas a basis to launch the effective pest managing strategies in the future. In this study, the development time, reproduction and population growth of two-spotted spider mite reared on the green bean variety TN38 and cucumber F1 (VA.103) were investigated at 23.5C. Results showed that the total immatures of male T. urticaewere not significantly different when reared onthebean and cucumberfor11.93 days and 11.73 days, respectively. However, the life cycle of female T. urticaereared on bean (13.69 days)wassignificantly shorter than its rearingon the cucumber (15.65 days). The oviposition rate and total number of eggs laid by the females fed on the bean (6.00 eggs/female/day and 62.69 eggs/female, respectively) were significantly higher than that of the female fed on cucumbers (3.13 eggs/ female/day and 29.35 eggs/female, respectively). The generation time (T) of the two spotted spider mite reared on bean (17.72 days)was significantly shorter than that on cucumbers (19.98 days). The net reproductive rate (R0) of the female fed on bean (45.02 females/female) was much higher than that of females reared on cucumbers (21.97 females/female). The intrinsic rate of natural increase of T. urticaeon bean was 0.210 which showed asignificantly higher than in cucumber (0.150).
Current Status and Solutions for Development of Medicinal Plants in the Central Highlands

Ninh Thi Phip, Nguyen Ba Hoat, Tran Duc Vien, Nguyen Duc Huy, Tran Van Quang, Bui The Khuynh, Vu Quynh Hoa, Nguyen Thi Thanh Hai, Bui Ngoc Tan, Vu Thanh Hai, Nguyen Duc Khanh, Le Huynh Thanh Phuong

Received: 27-02-2019 / Accepted: 03-09-2019
Medicinal plants are starting to be cultivated in the Central Highlands. In order to develop value chains of medicinal plants in the Central Highlands, it is necessary to investigate and assess the current situation. The PRA, key person interview and expert methods were used to collect data. Two districts in each province and 2 communes in each district were surveyed. The results showed that in order to develop medicinal herbs in a sustainable manner, it is necessary to conduct researches on varieties, planting area planning, appropriate farming techniques, preprocessing, processing and preservation of commodity products and adopt policies to encourage farmers and enterprises to join the medicinal value chain. The indigenous medicinal plants thantcan be developed in the Central Highlands include Vietnamese Ginseng (Panax vietnamensisHa et Grushv), Dang sam (Codonopsis javanica(Blume) Hook. f. & Thoms), Ngu vi tu (Schisandra sphenanthera) and Giao co lam (Gynostemma pentaphyllum). In addition, it is recommended to establish areas for the temperate medicinal herbs such as artichoke (Cynara scolymusL.) and (Angelica acutiloa Kitagawa), at the same time, expanding the area for intercropping like turmeric (Curcuma longaL.) amd Ginger (Zingiber officinaleRosc). In the central area of the Central Highlands, it is necessary to develop valuable commodity crops such as Crinum latifoliumL. and Ocimum gratissimumL. and testting new medicinal plants such as Polyscias fruticosaHarms) and Plukenetia volubilisL.
Effectof Salinity onOutbreak of Swollen Siphon Disease in Otter Clam(Lutraria philippinarumReeve, 1854)

Dang Thi Lua, Pham Thi Yen

Received: 15-03-2018 / Accepted: 29-01-2019
Swollen siphon disease has been considered to be a serious threat to otter clam farmingin Vietnam; however, the cause of the disease has not been clearly understood. In this study, salinity factor (salinity concentrations of 20‰, 25‰, 30‰, 35‰ and 40‰) was selected for evaluating its impact on the survival and outbreak of the swollen siphon disease in in vivoexperiments. The results showed that the otter clams died at salinity level less than or equal to 25‰and higher or equal to 35‰. However, the dead otter clamsdid not show any clinical signs of the swollen siphon disease. The results of the experiment of otter clam injected with diseased siphon’s filtrates and maintained at different salinity conditions ranking from 20‰to 40‰showedthat the salinity was significantly associated withmortality and outbreak of the swollen siphon diseaseshowing clinical signs. This study indicated that the salinity is not the cause of the swollen siphon disease in otter clam but it may be a risk factor that was significantly associated with the outbreak of the disease, particularly high salinitylevel(higher or equal to 35‰).
Đánh giá sự hài lòng về chất lượng dịch vụ của sinh viên Khoa Tế toán và Quản trị kinh doanh tại Học viện Nông nghiệp Việt Nam

Bui Thi Nga, Nguyen Thi Quynh Anh

Received: 02-02-2016 / Accepted: 24-06-2016
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.
Lý thuyết mới về đầu tư trực tiếp từ nước ngoài: Bằng chứng kiểm định từ trường hợp của Việt Nam

Hoang Chi Cuong , Tran Van Tho , Nguyen Thi Ngoc My

Received: 04-10-2013 / Accepted: 29-10-2013
Đầu tư trực tiếp nước ngoài (FDI) ngày càng trở nên quan trọng trong quá trình phát triển của Việt Nam. Sau hơn hai thập kỷ kể từ khi tiến hành đổi mới năm 1986, đất nước đã thu hút được một lượng lớn vốn FDI lên tới 229.913,7 triệu USD. Nghiên cứu này sử dụng mô hình lực hấp dẫn và phương pháp ước lượng Hausman-Taylor để kiểm tra xem liệu chỉ số tương đồng về quy mô kinh tế có thúc đẩy các dòng vốn FDI vào Việt Nam hay không. Vấn đề này có thể chưa được đề cập trong các nghiên cứu trước đây cho trường hợp của Việt Nam. Kết quả thực nghiệm cho thấy chỉ số này thúc đẩy mạnh mẽ các luồng vốn FDI vào Việt Nam. Nói cách khác, Việt Nam có xu hướng nhận được nhiều vốn FDI từ các đối tác có “quy mô kinh tế và trình độ phát triển tương đồng”. Kết quả này củng cố cho lý thuyết mới về FDI tại các nền kinh tế mới nổi.

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