Vol. 19 No. 7 (2021)

This study examined the differences in species composition and community structure of ground beetles among land use types of karst ecosystems in Huu Lien Nature Reserve (Lang Son Province). Pitfall traps were used to collect ground beetles. In total, 80 pitfall traps were established and distributed in four major types of land use comprising agricultural land, grassland, Acaciaplantations (10 years) and secondary forest (15 years). The study recorded 24 morphospecies of ground beetles from 477 trapped individuals. Agricultural land (maize field) had the highest abundance and species richness and a high level of diversity of ground beetles. The community structure of ground beetles significantly differed among the land uses. Particularly, the species ordination NMDS obviously separated the agricultural ground beetles from the forest communities. The litter layer significantly affected the community structure of ground beetles. The study found four ground-beetle species as bio-indicator species of the agricultural land based on the indicator value (IndVal), including: Pheropsophus jessoensis Morawitz, 1862, Chlaenius pleuroderusChaudoir, 1883, Harpalus indicusBates, 1891 and Chlaenius flavofemoratusLaporte, 1834.

This study aimed to provide information on the morphometric variations of Glossogobius aureus, a commercial fish species in the Mekong Delta. A total of 742 individuals (282 males and 360 females) were collected during the dry and wet seasons (January 2020 to December 2020) at four studied sites (Cai Rang, Can Tho; Long Phu, Soc Trang; Hoa Binh, Bac Lieu; and Dam Doi, Ca Mau). The results showed that total length and body weight of this species varied along with seasons and studied sites, but not genders. There were no significant differences in all morphological characteristics were not significant difference except the body length and weight variations of the immature and mature fish. The studied site and season variables influenced the total length and body weight of this species. The results of the present study have provided useful information for this species identification and understanding of the ecological adaptation of the fish in the study locations.

This study aimed to obtain more knowledge about the ecological characteristics of the natural seaweed communities in the coastal areas of Phu Quy archipelago, Binh Thuan province. Usingthe line-intercept method and SCUBA diving, we conducted a study of24 survey stations in the coastal areas of ​​Phu Quy archipelago from 2017 to 2018. The results showed that a total of 136 species belonging to 36families, 21 orders of 4 seaweed phyla was identified. Of the identified scpecies, the red seaweed (Rhodophyta) was the most abundant group with 67 species(44.85%). The seaweed species in Phu Quy archipelago were recorded in the tropical floras (P = 3.3). The seaweed species were mostly concentrated on hard bottomsfrom the tidal zone to the sub-tidal zone and a depth of 20m. The high biomass and density of seaweed were calculated at Hon Tranh Island. For example, the average coverage of seagrapes (Caulerpa) was 100% and the wet biomass weight from 500 to 10,880 g/m2in Hon Tranh Island; the coverage of brown seaweed (Sargassum) was from 35 to 60% and the wet biomass weight from 600 to 6.200 g/m2in the Mo Thay area, the East and Northwest of Phu Quy island. These research results are scientific bases for the conservation and development of seaweed communities in Phu Quy archipelago.

This study was to evaluate the effects of ecological conditions (high-density polyethylene (HDPE) lined pond, tank and lagoon) on the maturation of Scatophagus argus(Linnaeus, 1766).The experiment was conducted from 20thApril to20thJuly2020.Broodstock samples were randomly collected monthly to evaluate Gonado-somatic index (GSI), egg diameter, maturation rate, fecundity. The results show that the broodstock Scatophagus argus were able to mature under different ecological conditions. However, the maturation in the lagoon condition was better in Gonado-somatic index, egg diameter; and maturation rate than that of in pond and tank conditions (P <0.05). Similarly, the malehad a higher maturation rate when cultured in the lagoon. The male, stocked under three environmental conditions, had a relatively high maturation rate with an earlier maturation period. Gonado-somatic index and sperm quality were not changed during the experiment.

The Indoor Shrimp Production System (ISPS) with the treating water systems at low temperature was developed in Japan. This study evaluated the applicability and technical efficiency of growing white-leg shrimp in the ISPS under Vietnamese conditions. Two ponds in the ISPS were compared with two outdoor ponds overwinter in Nam Dinh. The ISPS ponds showed a better yield (51.84 ± 1.45ton/ha) and growth of shrimp (0.175 ± 0.006 g/day) compared with the outdoor ones. The phytoplankton communities of the two treatments were diverse; however, the cyanobacteria density in the ISPS pond water (<104cell/ml) was lower than the outdoor water (> 104cell/ml). The density of Vibrio parahaemolyticusin the ISPS pond water (0.6 101- 4.4 101CFU/ml) was lower than that in the probiotic one (1.2 103- 2.1 103CFU/ml) over 11 weeks. In addition, the total Vibrio and V. parahaemolyticus densities of the shrimp’s hepatopancreas in ISPS ponds (2.3 102 - 3.2 103CFU/ml và 1.1 102- 8.9 102 CFU/ml, respectively) were lower than those in the outdoor ones (1.5 103- 1.6 104CFU/ml và 8.3 103 - 9.8 103CFU/ml, respectively). The results demonstrated the potential applicability of the ISPS in culturing shrimp in the North of Vietnam.

This study was conducted to obtain an effective treatment regimen for intestinal nematodes Pallisentis of climbing perch (Anabas testudineus).Infected fish were randomly taken from an infected pond, examined for clinical signs and lesions of the fish intestine, calculated the prevalence and intensity of infection, and determined worm shape and size. Experimental treatments were levamisole 10mg/kg fish and praziquantel 25 mg/kg fish for 3 consecutive days, combined with anti-inflammatory and hemorrhagic treatment by florphenicol 15 mg/kg fish for five consecutive days. The results showed that fish were infected with pallisentisspp. at a high rate (100%), the average intensity of infection was 45 worms/fish, served hemorrhage of the intestines, intestinal perforation. Infected fish treated with levamisole combined with florphenicol resulted in the highest and most radical treatment effects, 100% of worms were killed, intestinal recovery and fish return to normal after five days of treatment.

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.

Cadmium (Cd) contamination of fish species is one of the most serious issues globally, due to fish play an important role in the human diet. The liver, gills, and muscles of Mottled spinefoot from Quang Binh (n = 50 per item) were collected to specify the variations of their cadmium content and assess their hazards towards human consumption. Cadmium content was analyzed by the flame atomic absorption spectrometer. The estimated daily intake (EDI) and target hazard quotient (THQ) were established to estimate the human health hazard. The concentration of cadmium tended to accumulate higher in the liver rather than gills and muscles. Although the majority of the cadmium content in the liver (at Quang Phuc, Ba Don and Nhat Le, Dong Hoi) and gills (at Nhan Le) exceeds the threshold limit value by the Ministry of Health, the EDI value in muscles was below the provisional tolerable daily intake and the THQ less than 1. Therefore, there is no potential risk of Cd to the consumer’s health of this species in the Quang Binh coastal area.

Currently, the global demand for development of biodegradable films to replace synthetic plastic materials has been rapidly increased. In this study, we aimed to extract lignin from sugarcane bagasse by-products of the sugarcane industry in order to fabricate biological membranes from chitosan and lignin to reduce environmental pollution. The results revealed that lignin was successfully extracted from sugarcane bagasse by alkaline hydrolysis method in 2h with weight ratio NaOH/ sugarcane bagasse of 1:10 w/w and precipitation at pH = 2 by acidic solution. Properties of films were measured: moisture, film thickness, tensile strength and waterproof. The biological waterproof films were synthesized from chitosan and lignin with a volume ratio (1C:1L v/v), the film thickness of 27,19-30,13µm and the tensile strength of 259.000-312.000 N/m2and antimicrobial activity with Escherichia coliandStaphylococcus aureus.

Research on introduced land snails was carried out from 2012 to 2020 in Northwest Vietnam (Lai Chau, Lao Cai, Dien Bien, Son La, Yen Bai, and Hoa Binh Provinces). A total of nine species (nearly 4.5% of the total number of land molluscs species in the research area) representing eight genera and five families were enumerated based on field surveys of 91 sampling sites. Five species (Lissachatina fulica, Allopeas gracile, Sarika resplendens, Bradybaena similaris, Succinea tenuis) were recorded frequently disturbed in habitats, while three species (Allopeas clavulinum, Chalepotaxis infantilis, Gulella bicolor) in relatively undisturbed habitats, and a species (Ganesella perakensis) in natural habitats. Of these, three species were considered to cause low risks (Allopeas clavulinum, Chalepotaxis infantilis, Ganesella perakensis), two medium risks (Gulella bicolor, Succinea tenuis), and four high risks (Lissachatina fulica, Allopeas gracile, Sarika resplendens, Bradybaena similaris). This paper’s data is urgently required to identify and manage introduced land snail species and if possible to prevent their spread to noninfected areas in Vietnam.

In oyster mushroom cultivation, it is very necessary to create new mushroom strains with more superior characteristics than cultivated strains.The three oyster mushroom strains PN1, PN14 and PN10 were used to generate hybrid combinations by single spore hybridization method and evaluated their hybrid combinations on the spawn culture and substrate cultivation. Thirty-eight single spore lines were isolated, including 18 single spore lines of PN1 strain, 16 single spore lines of PN10 strain and 4 single spore lines of PN14 strain. Seventy hybrid combinations have been implemented, of which three successful hybrid combinations were HP1-27 x HP14-4 (symbolized as PN1141), HP1-27 x HP14-7 (symbolized as PN1142), HP1-27 x HP14-10 (symbolized as PN1143) based on the appearance of clamp connection on the hyphae. On PDA medium, the hybrid strain PN1143 showed a lower growth rate than PN1 strain and higher than the remaining strains. On the spawn culture of boiled paddy, two strains of PN1 and PN1143 have the highest number of days to full colonization of substrates and growth rate of the hypha; the PN10 strain is lowest. On the cultivating substrate, 2 strains PN1 and PN1143 achieved higher results than the other strains in the growth rate of the hypha, fruit body size, biological efficiency were 55.46 and 54.54% respectively. The three strains of hybrid oysters are grayish-white, with stripes appearing on the mushroom caps.

Human resource selection is considered a vital factor for an organization or an enterprise, aiming to select the best candidates in order to meet the job requirements as well as the development of an organization or an enterprise in the future. Personnel selection is Multi-Criteria Decision-Making (MCDM) problem with many conflicting attributes. In this paper, we proposed a new fuzzy entropy measure to improve the calculation of weight of criteria in MOORA method. In addition, the proposed measure has also provided more options to calculate entropy measures of fuzzy sets. Finally, we applied the proposed model to the personnel selection for a training program and choosing the right accountant for a business. The obtained results are similar to those of other methods such as SWARA and FMCDM.

The process of land accumulation and concentration has occurredin Dak Nong province. However, this process still reveals many limitations and has not met the needs of the province's commodity agriculture development.Based onassessing the current situationand analyzing factors affecting the process of land accumulation and concentration over time, thisstudyproposedsolutions to accelerate the process of land accumulation and concentration for commodity-oriented agricultural developmentin Dak Nongprovince. This study appliedthe participatory approachmethodto collect primary data, combinedboth qualitative and quantitative methodsin data analysis. Ourresults showedthat for the farm group, land accumulation took place in the form of buying and renting land from other farmers, while for the cooperatives, land concentration in the form of sharing land rights between farmers and entrepreneurs was dominant. The fluctuation of the land market and the resources of the actors involved in land accumulation and concentration were key factors influencingthe process of land accumulation and concentration.