Zoogeographical division of Vietnam based on the oribatid mite (Acari: Oribatida) fauna

Soil oribatid mites (Acari: Oribatida) had been collected throughout Vietnam, including 50 sites located in 27 provinces, and from all of the 8 natural geographical regions. Up to December 2013, the oribatid fauna of Vietnam is represented by 320 species (including four subspecies) belonging to 163 genera, 64 families (including two subfamilies), and 30 superfamilies. 34.68% of the total number is probably endemic species. 155 oribatid species, representing 48.44% of the total oribatid fauna, were recorded for the first time for the fauna of Vietnam. The oribatid fauna of Vietnam occupies 3.09% (320 vs. 10,342 species), 13.05% (163 vs. 1,249 genera), and 38.0% (62 vs. 163 families) of the World oribatid fauna. Based on the analysis of the oribatid mite fauna, from North to South the zoogeographical division of Vietnam can be divided into six sub-divisions, as follows: (1) Region between Northwest and Northeast (North Vietnam), (2) Region of the Red River Delta (North Vietnam), (3) Region of the Red River Delta: National Park Cat Ba Island (North Vietnam), (4) Region of North Central: National Park Ben En (North Central Vietnam), (5) Region between the Uplands of the Red River Delta and the National Park Phong Nha - Ke Bang (North Vietnam and Central North Vietnam), and (6) Region of Southern (the Mekong River Delta): the National Parks of Bu Gia and of Cat Tien (South Vietnam)

A new semislug of the genus Laocaia (Gastropoda, Pulmonata, Helicarionidae) from Vietnam

A new species of the genus Laocaia Kuzminykh, 1999, Laocaia simovi Dedov & Schneppat, sp. nov., is described, which was collected from a single locality in northern Vietnam. Color pictures of living specimens are provided. For the first time, information on the ecology and biology of a representative of the genus Laocaia is presented

Consideration on lateral vibration of automobiles in quasi-planar model with wheel separation and road deformation taken into account

This article considers lateral vibration of an automobile in a so-called quasi-planar model where both the loss of contact and road deformation are taken into account. The automobile with dependent suspension is modeled as a vibration system which has two masses and four degrees of freedom. The deformed road is modeled as an elastic beam which has uniform rectangular cross-section, is simply supported at the two ends and lies on the Kelvin's visco-elastic ground. The loss of contact and the change in dimensions of contact areas are considered. The differential equations of motion of the vehicle-road coupled system which contains a partial differential equation are transformed into a set of all ordinary differential equations by applying the Bubnov-Galerkin’s method. A procedure for numerically solving the transformed differential equations of motion is proposed. Some illustrating results coming from numerical consideration are also presented in the paper

Consideration of the problem about vibration of automobile in one fourth model with taking road deformation and the loss of contact into account

This paper presents an approach to the problem about vibration of automobiles in one-fourth model where both road deformation and the loss of contact are taken into account. Contact characteristics such as the geometry of the contact area, pressure distribution, the relation between the contact force and the dimensions of the contact area, and therefore the change in dimensions of the contact area with respect to time are mentioned. Deformed road is modeled as an elastic beam which is simply supported at the two ends and lies on Kelvin’s visco-elastic ground. The differential equations of motion for both states of contact and losing contact are unified by introducing a so-called contact state parameter. The partial differential equation among the differential equations of motion of the vehicle-road coupled system is transformed into a system of all ordinary differential equations by applying the Bubnov-Galerkin’s method. A procedure for numerically solving the ordinary differential equations of motion of the vibration system under consideration is proposed and some numerical results for illustration are also presented in the paper

Warming threat compounds habitat degradation impacts on a tropical butterfly community in Vietnam

AbstractSpecies are threatened globally by multiple and often synergistic environmental changes including habitat loss, fragmentation and climate change. However, how these changes act in concert is poorly understood, especially in the tropics where the vast majority of biodiversity resides. Here, using a unique dataset covering 10~years of butterfly surveys (2003–2013) at Tam Dao National Park in northern Vietnam, we examined the combined impacts of habitat degradation (following intensive infrastructure development in 2005) and the possible threat of warming (extrapolating upon the relationship between natural climatic variation and community indices) for tropical butterfly communities. We found that both habitat degradation and warmer temperatures led to fewer narrow-range and forest-associated species comprising the sampled communities. Under projected climate change scenarios, the impact of warming was comparable to habitat degradation with respect to community change, and degraded forest communities were projected to shift towards cosmopolitan and non-forest species even more. The tropics have been heavily deforested world-wide and also suffer from heavy impacts of degradation and fragmentation, especially road construction. Warming will compound habitat degradation impacts such that the conservation of tropical biodiversity will require addressing these multiple global changes simultaneously

A Tourists' Travel Intention in the Context of Covid-19 in Viet Nam

The novel coronavirus pneumonia has seriously affected the development of tourism in Vietnam and even the whole world. Combining the current of VietNam's mitigation and the gradual recovery of tourism, this paper puts the research perspective on tourists' travel intention, and constructs a new theoretical structure by using TPB and TRA theory, This study presents the findings of a research which examined the relationship Subject norms and perceived behavioral control have a significant impact on Attitude and tourists' desire to travel;  the Attitude and desire to travel has a significant positive impact on tourists' travel intention, a little empirical study investigates these relationships together. This article investigates these relationships using SEM with data 437 tourists in the Vietnam. Findings of the study revealed that Attitude mediates the relationship between Subject norms, Perceived Behavioral Control, and Travel intention. Desire to travel mediates the relationship between Subject Norm, Perceived Behavioral Control and Travel intention. Based on the study findings, implications for theory and practice are discussed. Keywords: COVID-19, Theory of planned behaviour(TPB), Theory of reasoned action(TRA),Viet Nam DOI: 10.7176/EJBM/13-14-07 Publication date:July 31st 202

Development of a solar/LED lighting system for a plant tissue culture room

As the green energy, sunlight provides a friendly-environment and reduces electricity used for lighting. Our target is to enhance the use of natural energy and minimize the consumption of electricity for improving indoor environments. For this reason, a hybrid lighting system, combining sunlight with LEDs for plant tissue culture, are presented. The optical fiber daylighting system consists of three main parts: concentration, collimation beam, and transportation. The concentration part is formed by Fresnel lenses to collect and focus the sunlight into a small area by a non-imaging optical effect. The collimation part consists of optical filters and collimator lenses; the optical filters are used to reflect the ultraviolet (UV) and near infrared (NIR) regions, therefore, only the visible range of the solar light can be transmitted. The transportation part is a large-core optical fiber bundle. To increase the coupling efficiency, the collimator lens is used to expand and to collimate the focused light beam. The collimated light beam is then transported by the optical fiber bundle into a plant tissue culture room. In order to keep the plant tissue culture room at a constant illumination, a lighting control system based on LEDs is used to compensate variations of the natural light. In this paper, a prototype of optical fiber daylighting system and our proposed application will be presented.Ánh sáng mặt trời, một nguồn năng lượng xanh, được sử dụng cho chiếu sáng nhằm mang lại nguồn ánh sáng thân thiện với môi trường và giảm điện năng. Mục tiêu của chúng tôi là tăng cường sử dụng năng lượng tự nhiên và linh kiện tiêu thụ điện thấp để cải thiện môi trường ánh sáng trong nhà và giảm tiêu thụ điện cho chiếu sáng. Vì lý do này, một hệ thống chiếu sáng kết hợp ánh sáng mặt trời với đèn LED để nuôi cấy mô thực vật sẽ được trình bày. Hệ thống chiếu sáng ban ngày bằng sợi quang bao gồm ba phần chính:Bộ phận thu nhận và hội tụ ánh sáng, bộ phận chuẩn trực chùm sáng và bộ phận vận chuyển ánh sáng mặt trời tới nơi cần chiếu sáng. Phần tập trung được hình thành bởi một thấu kính Fresnel để thu thập và hội tụ ánh sáng mặt trời vào một vùng nhỏ bằng hiệu ứng quang học không tạo ảnh. Bộ phận chuẩn trực chumg sáng bao gồm bộ lọc quang học và thấu kính chuẩn trực. Bộ phận vận chuyển là các bó sợi quang lõi lớn. Bộ lọc quang học được sử dụng để phản xạ vùng cực tím (UV) và vùng hồng ngoại gần (NIR), chỉ cho phần ánh sáng nhìn thấy truyền qua. Để tăng hiệu quả ghép nối, thấu kính chuẩn trực được sử dụng để mở rộng và chuẩn trực chùm ánh sáng hội tụ. Chùm sáng chuẩn trực sau đó được vận chuyển bởi bó sợi quang vào phòng nuôi cấy mô thực vật. Để giữ cho phòng nuôi cấy mô thực vật được chiếu sáng liên tục, một hệ thống điều khiển ánh sáng dựa trên đèn LED để bù lại sự biến đổi của ánh sáng tự nhiên. Trong bài báo này, một nguyên mẫu của hệ thống chiếu sáng ban ngày bằng sợi quang và ứng dụng đề xuất của hệ thống sẽ được trình bày

Pro-poor intervention strategies in irrigated agriculture in Asia: poverty in irrigated agriculture: issues and options: Vietnam

Irrigated farming / Poverty / Farm income / Irrigation management / Institutions / Legal aspects / Water rates / User charges / Participatory management / Privatization / Participatory rural appraisal / Performance indexes / Irrigation programs / Irrigation systems / Pumping / Irrigation canals / Social aspects / Economic aspects / Rivers / Hydrology / Dams / Households / Income / Regression analysis / Drainage / Cooperatives / Water delivery / Water distribution / Rice / Financing / Drought / Vietnam / Red River Delta / Nam Duong Irrigation System / Nam Thach Han Irrigation System / Han River

EFFECT OF PRO-OXIDANT ADDITIVES ON DEGRADATION OF MULCH FILM BASED ON RECYCLED POLYETHYLENE

The effect of pro-oxidant additives (Iron, Cobalt and Manganese stearates) on the biodegradation of recycle polyethelene mulching films was studied in both accelerated weather and natural exposure conditions. The degradation degree of film was determined by measuring mechanical properties and scanning electronic microscope (SEM). The results showed that the mechanical properties of film samples with pro-oxirant additives decreased rapidly, and that surface film with additives was degraded clearly compared to the films without additives after 30 cycles of accelerated weather. Reliability in terms of acceleration are 28 - 30 cycles of exposure and in the natural conditions reached 10-12 months