Nonparametric estimation of the fragmentation kernel based on a PDE stationary distribution approximation

We consider a stochastic individual-based model in continuous time to describe a size-structured population for cell divisions. This model is motivated by the detection of cellular aging in biology. We address here the problem of nonparametric estimation of the kernel ruling the divisions based on the eigenvalue problem related to the asymptotic behavior in large population. This inverse problem involves a multiplicative deconvolution operator. Using Fourier technics we derive a nonparametric estimator whose consistency is studied. The main difficulty comes from the non-standard equations connecting the Fourier transforms of the kernel and the parameters of the model. A numerical study is carried out and we pay special attention to the derivation of bandwidths by using resampling

Capacity development platform for promoting efficient urban water management: Event Report

The present paper summarizes the results of an application initiated within the framework of 35 years celebration of diplomatic relations between Germany and Vietnam. Within this context, the Technische Universität Dresden (TUD) and the Academy of Managers for Construction and Cities (AMC) jointly organized in 2010 a series of four thematic workshops. The one-day events have had similar structures and focused on main subjects of interest in the water sectors of both countries. In Vietnam, the workshops took place in Ha Noi, Hai Phong, Nha Trang and Vung Tau. Best practice examples about conceptualization, operation and maintenance of municipal water works provided an insight view into the challenges currently faced by the water service providers. TUD and AMC, together with their German and Vietnamese partners, addressed these issues by organizing the consecutive workshops under the umbrella of Vietnamese Water Supply and Sewerage Association (VWSA) and in coordination with the German Water Partnership (GWP).Bài báo trình bày tóm tắt các kết quả của một đề xuất trong khuôn khổ kỷ niệm 35 năm quan hệ ngoại giao giữa CHLB Đức và Việt Nam. Theo đó, Trường Đại học Tổng hợp Kỹ Thuật Dresden (TUD) và Học viện Quản lý Xây dựng và Đô thị (AMC) đã phối hợp tổ chức một chuỗi bốn hội thảo chuyên đề trong năm 2010. Mỗi hội thảo thực hiện trong một ngày chương trình giống nhau và tập trung vào các chủ đề chính mà cả hai quốc gia đều quan tâm trong lĩnh vực nước. Phía Việt Nam, các hội thảo được tổ chức ở các thành phố Hà Nội, Hải Phòng, Nha Trang và Vũng Tàu. Nhiều bài thuyết trình về khái niệm hóa, vận hành và bảo dưỡng các công trình cấp nước đô thị đã thảo luận sâu về những thách thức mà các dịch vụ cấp nước đang gặp phải. TUD và AMC, kết hợp với các đối tác CHLB Đức và Việt Nam, đã ghi nhận các vấn đề phát sinh thông qua việc tổ chức nhiều hội thảo liên tục dưới sự bảo trợ của Hiệp hội Cấp thoát nước Việt Nam (VWSA) và Hiệp hội nước CHLB Đức (GWP)

Ultra high Performance Fiber Reinforced Concrete Panel Subjected to Severe Blast Loading

Experimental studies play a crucial role in shedding light on the dynamic behaviour of structures under blast loading. However, high costs and complicated technical requirements, particularly for full-scale structures, are still huge disadvantages to conduct such a series of tests. Hence, the finite element method is much needed to provide supplementary information to previous experiments and to enable further parametric studies without testing. This article presents a numerical investigation carried out to understand the behaviour of ultra high performance fiber reinforced concrete (UHPFRC) panels under severe blast loading. The authors designed a subroutine with eight numbers of solution-dependent state variables, 32 mechanical constants, integrated with the Abaqus program to analyze the dynamic behaviour of UHPFRC against multiple blast impacts, using the Johnson-Holmquist 2 damage model incorporating both the damage and residual strength of the material. The subroutine was validated by comparing the simulation results with test results. For the purpose of estimating the structural response of the UHPFRC panel subjected to blast loading, other studying scenarios were considered by varying input parameters, including the thickness of the panel, stand-off distance, and steel reinforcement bar volume. The variations in deflection, strain, and damage of the UHPFRC panel, as well as the steel reinforcement strain, were also evaluated. Through important obtained results, the UHPFRC panel is strongly recommended for a protective barrier installed in the vicinity of critical infrastructure against severe blast loadin

The pedagogical training management of gifted high school teachers in the region of Red River Delta based on a competency approach

Pedagogical training for teachers is always an important issue of every education system. Teachers impart knowledge, give academic advice to students, and assist students in applying knowledge to develop society. This study investigated the gifted high school teacher pedagogical training management in the region of the Red River Delta according to the competency approach. Based on the available data, the research indicated three main things: (i) Professional pedagogical competence of gifted high school teachers; (ii) Pedagogical training activities for gifted high school teachers; (iii) Management of pedagogical training activities for gifted high school teachers. This study conducted a survey of 547 departmental and school managers in gifted high school teachers in nine provinces in Red River Delta, including Hanoi, Ha Nam, Thai Binh, Nam Dinh, Hai Duong, Hung Yen, Bac Ninh, Quang Ninh, and Vinh Phuc. These findings are only preliminary research, and they will be an important basis for proposing management solutions to improve the effectiveness of pedagogical training activities for gifted high school teachers

Agroforestry - The Most Resilient Farming System for the Hilly Northwest of Vietnam

Over 94% of the land of northwestern Vietnam is classified as sloping. Population growth has exerted pressure on local natural resources, with agricultural expansion on steep slopes resulting in forest degradation, landscape fragmentation and severe environmental consequences. Efforts to restore forest ecosystems have been made by the government, however, as the livelihoods of 80% of the population depend on agriculture, the reconversion of land to forest has proven to be an inappropriate solution. Agroforestry offers a potentially sustainable land-use solution, which could re-establish forests, restore ecosystem services, and stabilize local livelihoods. In this paper, we assess the potential of agroforestry development in the region based on the results of two interrelated surveys conducted in 21 representative villages in six districts of three northwestern provinces: 1) a farming system diagnosis implemented in 17 representative villages; and 2) an agroforestry adoption survey with 210 households practising agroforestry in 14 villages. The analysis was strengthened by four years’ experience in implementing an extensive agroforestry project in the region. The studies focussed on assessing key benefits and constraints of existing farming systems, including agroforestry practices, adopted by farmers and identifying the potential for agroforestry development in the region. The results showed that the dominant farming system in the north-western provinces was monoculture of staple crops on slopes, which provided relatively low economic returns. Soil erosion, land degradation, and water shortages resultant from intensive farming practices were the most significant environmental issues in the area. Tree-based farming systems were rare and mostly a result of spontaneous adoption by farmers. Given the mountainous landscape and the need for soil stabilization, agroforestry was seen by farmers as a viable approach. Improving the existing and adopting new, integrated agroforestry systems were identified as viable ways toward sustainable livelihoods in Northwestern Vietnam

Exploring knowledge and attitudes toward the hepatitis B virus: an internet-based study among Vietnamese healthcare students

Context: Hepatitis B is a serious global public health problem, especially in developing countries such as Vietnam. Many studies worldwide have focused on health care workers, a population at high risk of infection with the hepatitis B virus (HBV), but there is little research that explores the high levels of risk faced by health care students. Aims: To assess the knowledge and attitudes of Vietnamese undergraduate students toward hepatitis B vaccination. Methods: A cross-sectional study was conducted among 1291 Vietnamese healthcare students between November 2017 and March 2018 via social media. Results: The mean score for knowledge was 4.0 ± 0.4, and the mean score for attitude was lower (3.5 ± 0.6). Levels of knowledge were higher (p<0.001) among sixth-year students, students who had been vaccinated, and students attending public universities. Most participants were well-informed about the diseases caused by HBV, with 1128 (87.4%) agreeing that HBV infection can lead to liver cancer. Nevertheless, 259 students believed that HBV cannot be spread by sharing a toothbrush with an infected person, and 18.7% thought that asymptomatic carriers are incapable of transmitting HBV. Conclusions: Although students had adequate knowledge of HBV, their scores for attitude and their rates of vaccination were low. This study therefore recommends improving the knowledge and attitudes of health care students through orientation and sensitization programs and improvements in their educational environment

ẢNH HƯỞNG CỦA MÔI TRƯỜNG NUÔI CẤY LÊN SINH TRƯỞNG CỦA CALLUS CÂY GIẢO CỔ LAM (Gynostemma pentaphyllum (Thunb.) Makino) – MỘT CÂY DƯỢC LIỆU CÓ GIÁ TRỊ

Gynostemma pentaphyllum (Thunb.) Makino (Jiaogulan) is a traditional medicinal herb belonging to the Cucurbitaceae family. G. pentaphyllum grows widely in Southern China, Japan, Korea, and Vietnam. The essential bioactive components of Jiaogulan are saponin glycosides (gypenosides) and antioxidants. Jiaogulan exhibits bioactive activities such as anticancer, antioxidant, cholesterol-reducing agent, immunopotentiation, and others. In this study, the primary callus of Jiaogulan was used as a material to evaluate the influence of the culture medium on the induction and growth of secondary calli. The results reveal that the callus cultured on the MS medium supplemented with 2.0 mg/L kinetin and 0.5 mg/L indole-3-butyric acid has the best growth ability, high rate of secondary callus induction (100%), and good callus quality for suspension culture. The concentration of gypenoside and Rb1 in callus is 36.298 and 0.009 mg/g dry weight. The gypenoside concentration of callus is lower than that of leaves (65.58%) and almost similar to that of stems (92.38%) from natural samples. The suitable solvent for the extraction of gypenoside is methanol. The obtained callus will be used as material for cell suspension culture in further studies.Giảo cổ lam (Gynostemma pentaphyllum (Thunb.) Makino) là một cây thuốc dân gian thuộc họ Bầu bí. Cây phân bố rộng ở miền Nam Trung Quốc, Nhật Bản, Hàn Quốc và Việt Nam. Các thành phần có hoạt tính sinh học quan trọng của Giảo cổ làm là saponin glycoside (gypenoside) và các chất chống oxy hóa. Giảo cổ lam được sử dụng hỗ trợ chống ung thư, chống oxy hóa, giảm cholesterol, tăng cường miễn dịch và các tác dụng khác. Trong nghiên cứu này, callus sơ cấp của cây Giảo cổ lam được sử dụng làm nguyên liệu để đánh giá ảnh hưởng của môi trường nuôi cấy lên khả năng phát sinh và sinh trưởng của callus thứ cấp. Kết quả cho thấy, callus được nuôi cấy trên môi trường MS có bổ sung 2,0 mg/L kinetin và 0,5 mg/L indole-3-butyric acid sinh trưởng tốt nhất; tỷ lệ tạo callus thứ cấp cao (100%); callus đáp ứng được tiêu chuẩn để nuôi cấy huyền phù. Hàm lượng gypenoside và Rb1 trong callus là 36,298 và 0,009 mg/g chất khô; gypenoside thấp hơn trong lá (65,58%) và gần tương đương với mẫu thân (92,38%) của sản phẩm thu mua từ thị trường. Dung môi thích hợp để tách chiết gypenoside là methanol. Callus thu được sẽ được sử dụng làm nguyên liệu cho nuôi cấy tế bào huyền phù trong các nghiên cứu tiếp theo