Neochrysocharis okazakii

Liriomyza chinensis is a major pest of Welsh onion Allium fistulosum in Asia but little is known about the abundance of its natural enemies. A field survey was made to explore the major parasitoids of L. chinensis leaf miner in central Vietnam. An eulophid parasitoid, Neochrysocharis okazakii, comprised more than 95% of parasitoids reared from leaf miner larvae collected in the onion field and 98.3% of leaf miner parasitoids found during searches of onion plants. The mean number of female N. okazakii on plants was greater in onion fields with a higher density of L. chinensis, and, during searches, a greater proportion of N. okazakii was found on onion with more L. chinensis mines, suggesting density-dependent parasitoid aggregation. Melanized dead larvae of L. chinensis were more frequently found in onion fields with more parasitoids, demonstrating that melanized leaf miners are a good indicator of parasitoid activity. Mean instant rate of host encounter by N. okazakii in the field was estimated at 0.077, and the likelihood of a parasitoid finding a host increased with host density. Taken together, these results show that N. okazakii is the major parasitoid of L. chinensis. Usefulness of this parasitoid in stone leek leaf miner management is discussed

A Study on Employment for Rural Laborers in the Process of Industrialization and Modernization of Vietnam

Employment and job creation are global socio-economic issues and concern every country in the world and Vietnam is no exception. Today, the concept of development is comprehensively understood and economic growth is associated with progress, social justice, poverty reduction, on the basis of creating sustainable jobs for workers. At different times, employments for workers also have different characteristics. In the dimension of this study, employment for rural laborers with the case study of Nam Dinh of Vietnam have been investigated, then some recommendations are proposed for creating more jobs for rural people. Keywords: Employment, job creation, rural employment, rural labor. DOI: 10.7176/EJBM/12-21-13 Publication date:July 31st 202

Phase Structure of Bose - Einstein Condensate in Ultra - Cold Bose Gases

The Bose - Einstein condensation of ultra - cold Bose gases is studied by means of the Cornwall - Jackiw - Tomboulis effective potential approach in the improved double - bubble approximation which preserves the Goldstone theorem. The phase structure of Bose - Einstein condensate associating with two different types of phase transition is systematically investigated. Its main feature is that the symmetry which was broken at zero temperature gets restore at higher temperature

ĐÁNH GIÁ THỰC TRẠNG CANH TÁC DỪA TẠI ĐẢO PHÚ QUỐC, TỈNH KIÊN GIANG

Coconut trees (Cocos nucifera L.)  are a popular crop on more than 30,000 islands around the world, with many uses and livelihood values for farmers. The study was conducted to evaluate the current status of coconut farming on Phu Quoc Island by interviewing farmer households. The results showed that coconut trees were planted in Cua Duong and Cua Can communes with growing areas ranging from 0.2 to 0.8 hectares per household, mainly in the form of specialised cultivation with two popular coconut varieties which were oil coconut and drinking coconut. Coconut oil varieties ranged in age from 1 to 15 years, flowering time from 4.0 to 5.0 years after planting, and yield from 40 to 60 fruits per tree per year. Drinking coconut varieties were less than 10 years old; flowering time was from 3.0 to 4.0 years after planting; and yielding was from 50 to 100 fruits per tree per year. The form of fruit sales on Phu Quoc Island was mainly drinking coconuts purchased, with harvests ranging from 10 to 15 times per year. The investment cost for coconut gardens of households the business period mainly under 10 millions VND and average incomes under 20 millions VND per hectare per year, respectively.Cây dừa (Cocos nucifera L.) là cây trồng quan trọng ở các vùng biển đảo, được trồng phổ biến ở hơn 30.000 hòn đảo trên thế giới với nhiều giá trị sử dụng và là sinh kế của người nông dân. Nghiên cứu được thực hiện nhằm đánh giá thực trạng canh tác dừa tại đảo Phú Quốc, tỉnh Kiên Giang bằng phương pháp thu thập số liệu thứ cấp và phỏng vấn nông hộ. Kết quả cho thấy, cây dừa được trồng tập trung tại xã Cửa Dương và xã Cửa Cạn với diện tích từ 0,2 đến 0,8 ha/hộ, chủ yếu là hình thức chuyên canh với hai nhóm giống dừa phổ biến là lấy dầu và uống nước. Giống dừa lấy dầu có độ tuổi từ 1 đến 15 năm, thời gian ra hoa từ 4,0 đến 5,0 năm sau trồng và năng suất từ 40 đến 60 quả/cây/năm. Giống dừa uống nước có độ tuổi dưới 10 năm, thời gian ra hoa từ 3,0 đến 4,0 năm sau trồng và năng suất từ 50 đến 100 quả/cây/năm. Hình thức bán quả dừa tại đảo Phú Quốc chủ yếu là uống nước với số lần thu hoạch từ 10 đến 15 lần/năm. Chi phí chăm sóc vườn dừa trong thời kỳ kinh doanh chủ yếu dưới 10 triệu đồng/ha/năm với lợi nhuận đa số dưới 20 triệu đồng/ha/năm

Biocompatible chitosan-functionalized upconverting nanocomposites

Simultaneous integration of photon emission and biocompatibility into nanoparticles is an interesting strategy to develop applications of advanced optical materials. In this work, we present the synthesis of biocompatible optical nanocomposites from the combination of near-infrared luminescent lanthanide nanoparticles and water-soluble chitosan. NaYF4:Yb,Er upconverting nanocrystal guests and water-soluble chitosan hosts are prepared and integrated together into biofunctional optical composites. The control of aqueous dissolution, gelation, assembly, and drying of NaYF4:Yb,Er nanocolloids and chitosan liquids allowed us to design novel optical structures of spongelike aerogels and beadlike microspheres. Well-defined shape and near-infrared response lead upconverting nanocrystals to serve as photon converters to couple with plasmonic gold (Au) nanoparticles. Biocompatible chitosan-stabilized Au/NaYF4:Yb,Er nanocomposites are prepared to show their potential use in biomedicine as we find them exhibiting a half-maximal effective concentration (EC50) of 0.58 mg mL–1 for chitosan-stabilized Au/NaYF4:Yb,Er nanorods versus 0.24 mg mL–1 for chitosan-stabilized NaYF4:Yb,Er after 24 h. As a result of their low cytotoxicity and upconverting response, these novel materials hold promise to be interesting for biomedicine, analytical sensing, and other applications

THỰC TRẠNG CANH TÁC DỪA TẠI TỈNH BẾN TRE, VIỆT NAM

Coconut is an important cash crop in Ben Tre Province, Vietnam, which has a lot of value. This study aimed to determine the current status of coconut cultivation in Ben Tre province through secondary data collected from the Ben Tre Provincal Statistical Office as well as primary data provided by 150 farmers in five coconut cultivated districts consisting of Chau Thanh, Giong Trom, Ba Tri, Thanh Phu, and Binh Dai via participatory interview method. The results showed that coconut planting and harvesting areas in Ben Tre province have been a significant increase over the period from 2012 to 2022, with production increasing by 1.6 times, reaching 686,279 tonnes in 2022. The predominant coconut cultivated method was specialised farming, with most households using tall coconut varieties. Planting density ranged from 160 to 240 trees per hectare. Flowering of the coconut plants was within 3 to 6 years of planting. Fertilization application was 4 to 6 times year-1 during the business period. Besides, insect pests and diseases on the coconut plants had been controlled by pesticides with 3 to 6 times per year. Coconut fruit yields were depended on variety and cultivation techniques, averaging 80 to 100 fruits tree-1 year-1 and 40 to 80 fruits tree-1 year-1 for dwarf and tall coconuts, respectively. The investment cost for coconut gardens ranged from 10 to 30 million VND hectare-1 year-1, with average incomes of 30 to 100 million VND hectare-1 year-1, yielding profits of 30 to 60 million VND hectare-1 year-1.Cây dừa là cây trồng quan trọng của tỉnh Bến Tre có nhiều giá trị sử dụng. Nghiên cứu này nhằm đánh giá thực trạng canh tác dừa tại tỉnh Bến Tre dựa trên số liệu thứ cấp từ Cục Thống kê tỉnh Bến Tre và số liệu sơ cấp thông qua phỏng vấn 150 hộ trồng dừa tại 5 huyện gồm Châu Thành, Giồng Trôm, Ba Tri, Thạnh Phú và Bình Đại. Kết quả cho thấy, diện tích trồng và thu hoạch dừa tại tỉnh Bến Tre có xu hướng tăng mạnh trong 10 năm (2012–2022), sản lượng tăng gấp 1,6 lần và đạt 686.279 tấn vào năm 2022. Hình thức canh tác dừa chủ yếu chuyên canh, phần lớn các hộ sử dụng giống dừa cao, mật độ trồng dao động 160–240 cây/ha, cây dừa bắt đầu ra hoa sau 3–6 năm trồng, số lần bón phân trong thời kỳ kinh doanh là 4–6 lần/năm, quản lý sâu bệnh hại dừa chủ yếu bằng thuốc bảo vệ thực vật với 3–6 lần phun/năm. Năng suất dừa phụ thuộc vào giống và kỹ thuật canh tác, trung bình 80–100 quả/cây/năm đối với dừa lùn và 40–80 quả/cây/năm đối với dừa cao. Chi phí đầu tư cho vườn dừa 10–30 triệu đồng/ha/năm, thu nhập bình quân 30–100 triệu đồng/ha/năm và đem lại lợi nhuận 30–60 triệu đồng/ha/năm

Tri-axis convective accelerometer with closed-loop heat source

In this paper, we report the details and findings of a study on tri-axis convective accelerometer, which is designed with the closed-loop type heat source and thermal sensing hotwire elements. The closed-loopheat source enhances the convective flow to the central part where a hotwire is placed to measure the vertical component of acceleration. The simulation was conducted using numerical analysis, and the devicewas prototyped by additive manufacturing. The device, functioning as a tilt sensor and an accelerometer,was tested up to acceleration of 20 g. The experiments were successfully conducted and the experimental results agreed reasonably with those obtained by numerical analysis. The results demonstrated that the closed-loop heat source could reduce the cross effect between the acceleration components. The scalefactor and cross-sensitivity had the values of 0.26 micro�V/g and 1.2%, respectively. The cross-sensitivity andthe effects of heating power were also investigated in this study

OVERALL ASSESSMENT OF DEFORMATION AND FORCE OF DIAPHRAGM WALL JOINTS DURING THE STAGES OF DEEP EXCAVATION CONSTRUCTION

In the realm of geotechnical engineering, deep excavation projects face intricate challenges, especially concerning the stability of barrette walls, which are highly susceptible to deformation and stress at their joints. This study focuses on evaluating the deformation and force behavior of barrette wall joints at the position of greatest deformation. The Finite Element Method (FEM) is utilized to simulate the behavior of these structures under various load conditions. The Analysis of Variance (ANOVA) method is employed to statistically analyze the FEM data, assessing the impact of different factors on deformation and force distributions within the barrette wall joints. The specific objective of this study is to determine the statistical significance of the observed deformations and understand the influence of construction stages on joint integrity. This methodological synergy enhances the predictability of engineering assessments and ensures that design and construction decisions are grounded in solid empirical evidence. The study's findings emphasize the importance of precise monitoring and advanced predictive techniques to mitigate potential risks associated with deep excavations, particularly at critical joint locations. The results indicate that the deformation patterns are primarily influenced by the geometrical setup of the walls and the mechanical properties of the soils. The greatest deformations were typically observed where the wall joints experienced the highest bending moments and shear forces, conditions exacerbated by unfavorable soil mechanics and hydrostatic pressures. The clear and consistent increase in total displacement highlights the progressive destabilization of the wall as the excavation depth increases. By integrating ANOVA with FEM, this study contributes to enhancing safety and efficiency in deep excavation projects by ensuring that decisions are grounded in empirical evidence