Topological Lifshitz phase transition in effective model of QCD with chiral symmetry non-restoration

The topological Lifshitz phase transition is studied systematically within an effective model of QCD, in which the chiral symmetry, broken at zero temperature, is not restored at high temperature and/or baryon chemical potential. It is found that during phase transition the quark system undergoes a first-order transition from low density fully-gapped state to high density state with Fermi sphere which is protected by momentum-space topology. The Lifshitz phase diagram in the plane of temperature and baryon chemical potential is established. The critical behaviors of various equations of state are determined.Comment: 8 pages, 10 figure

2D-model of contaminant water transmission processes and numerical simulation on a natural lake

Nowadays, the water pollution problems in the lakes are urgent matters. The simulation of contaminant water transmission process plays important role in reality to improve people's life qualities. In this paper the 2D-mathematical model simulating transmission processes of some contaminant substances in one lake of Hanoi is studied. The finite volume method is used in model. The actions between substances are considered and the simulation results are compared with the measurements

On the motion of incompressible viscous fluid with flotation on free surface

Non

Improving microinsurance services quality in Vietnam women's union, the case study at Vietnamese microinsurance fund

Microinsurance fund (MIF) that belongs to Vietnam Women’s Union (VWU) is one of the youngest micro insurers in Vietnam that officially entered microinsurance service market in the upward trend of competition since 2007. This fund only took up a very small part in the total insurance market share. To get effective competition, the prerequisite for Microinsurance fund is to give clients new microinsurance products with higher quality. In addition, the fund must continuously research, explore and improve existing product in order to create different product package compared to other insurers. This is the only way for them to gain competitive advantage, maintain customer loyalty and increase the fund’s market share in the microinsurance market. To do that, Microinsurance Fund needs to find the right strategy and Blue Ocean Strategy (BOS) will be the best choice for MIF in coming time. The aim of applying the theory on BOS is not to create the competition in the existing insurance industry, but to create new market space or a blue ocean, thereby making the pursuit of differentiation and low cost. This thesis focuses on analyzing and finding how Microinsurance Fund applies BOS for developing microinsurance products with following objectives. Firstly, it is to analyze current value of credit life microinsurance product in Vietnam insurance market. Secondly, it is to apply concept of BOS to recommend solutions for developing new microinsurance products in Microinsurance Fund. As for methods, the questionnaire’s survey and direct interviews were used for traditional clients, beneficiaries, TYM staffs and commune authorities. The earlier research and results of this thesis show that there are some key value aspects related to microinsurance products. These value aspects include product features, premiums, claim investigation work, quality of staff, product distribution channels, quality of customer service, advertising and promotion policies and insurer’s brand and reputation. I applied the four actions framework model of BOS theory for developing new microinsurance products. Finally, the author has tried to recommend solutions for Microinsurance Fund with “cost leadership” for developing new microinsurance products, including life and non –life insurance products. This cost is strategy used by almost companies in order to create a low cost of operation and to achieve in advance over rivals by cutting down other costs that of others in the insurance industry

Factors affecting the teaching and learning of English in a blended learning environment in a Vietnamese university

The adoption of blended learning solutions in higher education has increased significantly over some years in many developing countries, including Vietnam. While blended learning has been well-researched in Western countries such as the USA, the UK and Australia, little has been known about blended learning in Vietnamese contexts. Previous research has indicated that the adoption of blended learning in higher education can be affected by numerous factors. Thus, my study aims to add to this research, by exploring factors that affect the teaching and learning of English in a blended learning approach in a Vietnamese university. I used a mixed methods design approach for gathering data. Quantitative data were collected from an online survey to 339 English as a Foreign Language (EFL) second-year students at the university. Qualitative data were collected from semi-structured interviews with 7 students, 3 programme leaders (PLs) and 5 teachers at the university. The collected data were then analysed and interpreted using Engeström’s (1987) Activity Theory as a framework. Key findings indicated that the PLs’ design activity, teachers’ works and students’ learning in their English blended courses were mediated by the Learning Management System (LMS) structure, the institutional regulations and their roles and responsibilities. The PLs and the teachers viewed the LMS as having affordances including helping deliver learning content materials and monitor students’ online task completion. However, the constraints of the LMS such as a lack of communicational tools within the LMS and its behaviouristic features hindered students’ blended learning experience. These constraints also prompted the teachers to use communicational tools external to the LMS to interact with students. The institutional requirements were also found to influence blended learning design decisions and teaching activities. Several online learning challenges inhibited students’ blended learning experience including students’ limited self-regulated learning skills, teachers’ inadequate online facilitation; online assessment issues; and technical problems. This study has several implications and recommendations for Vietnamese higher education institutions who wish to implement EFL blended learning. These include raising institutional awareness of developing blended learning programmes to fit intended educational outcomes, considering students’ knowledge and skills needed for blended courses, and providing ongoing professional development and support for both designing and teaching staff. Moreover, addressing technical issues and improving the LMS will make learning and teaching experiences of blended courses more rewardin

The Potential of Beauveria against Root Mealybugs Formiccoccus sp. (Homoptera: Pseudococidae) Black Pepper in Dak Lak Province of Vietnam

Root mealybugs Formicoccus sp.(Hemiptera: Pseudococcidae) currently emerge as an economically important soil-borne insect pest in the production of black pepper (Piper nigrum L.) in Dak Lak province of Vietnam. Entomopathogenic fungi can be used in agricultural production as feasible safe biocontrol agents and plant growth promoters. This study aimed to isolate, select and identify the local Beauveria sp. strains from the black pepper fields, as well as evaluate the effects of the selected strains on the growth of black pepper. The results showed that the frequency of positive Beauveria sp. soil samples collected from organic black pepper fields was significantly higher than that from conventional black pepper fields. Twenty-one Beauveria sp. strains in black pepper organic fields and four Beauveria sp. strains in black pepper conventional fields were successfully isolated, among them, the Beauveria bassiana BB1 was examined and evaluated for its biocontrol potential against Formicoccus sp. and its ability to promote the growth of black pepper seedlings. In the laboratory experiments, the mortality of both adults and first instar nymph root mealybugs Formicoccus sp. caused by B. bassiana BB1 culminated 100% at 21 days after treatments. In the nethouse, at 6 months after treatment, the efficacy of B. bassiana BB1 against black pepper root mealybugs reached 99.18%. The levels of photosynthetic pigments in the leaves of the black pepper seedlings increased about 2 times compared to the control. Moreover, B. bassiana BB1 strain also remarkably promoted the growth of the black pepper seedlings under the nethouse conditions

Pecuniary versus Non-pecuniary Interventions to Influence Farmers’ Behavior: Evidence from Field Experiment in Vietnam

Encouraging farmers to adopt pro-environmental production is vital to the promotion of sustainable agriculture. Previous observational studies emphasize the importance of economic incentives and information access to the farmer's decision; however, due to endogeneity issues, little strong causal evidence is available. This study makes an original contribution by experimentally examining the impacts of subsidy and information treatments on farmers' adoption of organic fertilizer. To do so, we analyze data from a randomized controlled trial (RCT) conducted on 1287 small-scale tea farmers in Vietnam. We find significant impacts of our information treatment and a 50% price subsidy. Interestingly, the effect of the former is approximately one-third that of the latter. Subgroup treatment analysis reveals that the information treatment performs well for members of certification groups. Thus, to induce farmers to adopt pro-environmental production behaviors, information provision can partially substitute for subsidies to reduce the burden on the public budget.This work is supported by JSPS KAKENHI Grant Numbers 18J13432 and 17K03692.SUPPLEMENTAL MATERIALS: pp.1-

General sensitivity analysis in data assimilation

International audienceThe problem of variational data assimilation for a nonlinear evolution model is formulated as an optimal control problem to nd the initial condition function (analysis). The operator of the model, and hence the optimal solution, depend on the parameters which may contain uncertainties. A response function is considered as a functional of the solution after assimilation. Based on the second-order adjoint techniques, the sensitivity of the response function to the parameters of the model is studied. The gradient of the response function is related to the solution of a non-standard problem involving the coupled system of direct and adjoint equations. The solvability of the non-standard problem is studied. Numerical algorithms for solving the problem are developed. The results are applied for the 2D hydraulic and pollution models. Numerical examples on computation of the gradient of the response function are presented

Convection in binary mixture with free surface

Non

NGUỒN GIỐNG TÔM, CÁ VÙNG NƯỚC VEN CÁC ĐẢO THUỘC QUẦN ĐẢO TRƯỜNG SA

Belonging to the Indo - Pacific tropical marine biodiversity Central, marine living communities at the coastal waters of Islands of Truong Sa Archipelago plays the important roles in conservation and cover distribution the breeds of marine living resources (including larva forms of shrimp, fish anf others) not only in this areas but also in the neughbour waters. However, due to far from mainlands, the studies on them is limited to now. Samples was collected at the 3 - 7 transects with long 100m to 30 - 50m deepth, where is around some island such as Nam Yet, Da Nam, big Truong Sa, Song Tu Tay ... There are two stations was located on every transect for sampling the species composition and individual numbers of larva. Samples was catched by net with 200µ diameter in the vertical drawing following the water colum. This primary results that were identified including 46 taxons of fish, shrimp and others larva. Most of them are belonging to the coral fish anh shrimp and the widely distribution ecological groups having high econimic value such as: Labridae, Scaridae, Nemipteridae, Nephridae, Palinuridae ... The spatial taxon of larva diversity distribution is not very regular every island. The taxon diversity at the big Truong Sa, Nam Yet, Da Nam ones is higher than the others with 18 - 31 taxons/island. The others is have only about 10 taxons/islands. The medium individual number of larva is rather higher than that in the other sites which is in nearshore water with about 300 inds/100m3. The highest concentration of inds number of fish and shrimp larva is at the stations having good coral reefs.Nằm trong vùng biển nhiệt đới là một trong những trung tâm đa dạng sinh học và phát sinh các loài thuộc vùng địa động vật Ấn Độ - Thái Bình Dương, nên quần xã sinh vật vùng biển và ven  các đảo Trường Sa có vai trò rất quan trọng trong việc duy trì và phát tán nguồn giống các loài sinh vật thuỷ sinh  cho  các vùng biển lân cận. Tuy nhiên do điều kiện địa lý xa cách, nên những nghiên cứu về sinh vật phù du nói chung và  nguồn giống các loại động vật thuỷ sản như tôm, cua, cá và thân mềm nói riêng ở vùng nước quanh các đảo vùng biển Trường Sa còn rất hạn chế. Kết quả trong bài báo thống kê từ kết quả khi thu mẫu các loại ấu trùng tôm, cá trên 3 - 7 mặt cắt (mỗi mặt cắt 2 trạm) thuộc 9 đảo tại quần đảo Trường Sa trong năm 2007 - 2008 do đề tài nghiên cứu cơ sở khoa học xây dựng các khu bảo tồn biển quần đảo Trường Sa tổ chức. Kết quả nghiên cứu cho thấy thành phần nguồn giống gồm 46 taxon là ấu trùng các giai đoạn của tôm, cua, cá và thân mềm. Trong đó có 26 taxon là ấu trùng cá, 16 taxon là ấu trùng tôm, 5 taxon ấu trùng cua và thân mềm. Hầu hết đều là các loại cá, tôm có giá trị kinh tế và chỉ thị tốt cho rạn san hô (RSH) như: Labridae, Scaridae, Nemipteridae, Nephridae, Palinuridae. Kết quả cũng xác định khu vực quanh đảo Trường Sa lớn, Nam Yết và Đá Nam thành phần nguồn giống đa dạng nhất với 18 - 31 đơn vị taxon. Mật độ trung bình của  ấu trùng tôm, cá khá cao tới hơn 300 con/100m3, cao hơn một số khu vực ven các đảo gần bờ và có sự tập trung mật độ cao nhất tại các nơi có RSH phát triển tốt nhất