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The paper provides a short review of Bulbophyllum species recorded in Laos and Vietnam during the two last decades and continues the publication of results of our successive studies of the genus in this area. It presents data on two new species for science discovered in Laos (Bulbophyllum pachypodum) and Vietnam (B. neglectipetalum), one lesser known species for the flora of Laos (B. microtepalum), two new records for the flora of Vietnam (B. echinulus, B. setilabium), and new illustrated data on B. secundum insufficiently known in the flora of Vietnam. Bulbophyllum fascinator earlier accepted in specific rank reduced into the synonymy of B. putidum on the base of studies of newly obtained materials. Taking into consideration the new data presented in this paper, the flora of Laos presently includes 85, and flora of Vietnam 151 Bulbophyllum species, excluding Monomeria, Trias, and Sunipia. It is the largest genus in the orchid floras of both countries.

This paper presents new data on the orchid diversity of Vietnam obtained in 2015–2021. It contains descriptions of three new species (Cleisostoma furcatum, Malleola micrantha, Schoenorchis hungii), one new variety (Chiloschista parishii var. minutiflora) and one new form (Cleisostoma furcatum forma albiflora). Additionally six species, Ascocentropsis malipoensis, Chiloschista sweelimii, Pomatocalpa undulatum, Trachoma rhopalorrhachis, Trichoglottis maculata, and Uncifera acuminata are newly recorded for Vietnam. The paper also provides an amended description of a very rare and poorly known species, Cleisostoma equestre. All studied taxa belong to subtribe Aeridinae (tribe Vandeae, subfamily Epidendroideae). The accepted plant name, main synonyms, data on type specimens, ecology, phenology and distribution, estimated IUCN Red List status, studied specimens, brief taxonomic notes, and illustrations are provided for each species listed.

This paper presents a massage-treatment prototype on acupuncture points whose method of detecting is based on differences of blood oxygen saturation ratio. Sensor MAX30100 is used to measure blood oxygen saturation (SpO2) of more than 20 people in bright room conditions with an intensity of 115 lx and an ideal dark room condition. Then based on Beer's law of absorbance and experiment, we determined that the points with SPO2 concentration over 99.2% are the locations of the acupuncture ones in order to perform biological massaging pulse. The main scientific principle is the diffuse remittances of diverse red led from meridian and acupuncture point that make blood oxygen saturation levels higher than other areas. In the experiment, we also consider prudently the results of tissues surrounding acupuncture points with the distance of 5, 10 and 20 mm and the influence of that to the final outcome. In general, the final result is reliable with moderate accuracy. However, there are some drawbacks in this system such as errors for people who have inappropriate skin surface for optical detection.

In this paper, we study a Cauchy problem for the heat equation with linear source in the form ut(x,t)= uxx(x,t)+f(x,t), u(L,t)= φ(t), u(L,t)= Ψ (t), (x,t) ∈ (0,L) ×(0, 2π). This problem is ill-posed in the sense of Hadamard. To regularize the problem, the truncation method is proposed to solve the problem in the presence of noisy Cauchy data φε and Ψε satisfying ‖ φε - φ ‖+‖ Ψε - Ψ ‖ ≤ ε and that fε satisfying ‖ fε(x,. ) - f(x,.) ‖ ≤ ε . We give some error estimates between the regularized solution and the exact solution under some different a-priori conditions of exact solution.

The purpose of this study is to analyze the trend of precipitation change in Ninh Thuan province in the context of Climate Change. In this study, the authors used precipitation data at rain gauges with a minimum duration of 24 years and a maximum of 36 years. The main method was used in this study is the non-parametric method, namely Mann-Kendall analysis and the Theil-Sen slope. The research was conducted under the support of ProULC 5.1 and MAKESEN 1.0 software. The results showed that annual rainfall in Ninh Thuan province tended to increase in the time series of observation. Specifically, the downward trend of rainfall was mainly in March and increased from July to November. Along with that, through the index regarding the trend of increase and decrease of rainfall, the study also showed a prediction of the trend of increasing rainfall for the area. Forecast results of 2035 rainfall in Ninh Thuan the highest the increase is expected 7.7% and in 2050 is 13.8%. The study results have reflected the actual situation of rainfall change in the context of climate change with the stations having statistical significance (p

Eco-certification has been used as a tool to mitigate adverse effects of aquaculture production and might thus be understood as a private approach to sustainable ecosystem management. In production forests in Ca Mau, Vietnam, where mangrove have suffered degradation despite legal protection, different projects have targeted reversing this trend by means of private certification using the ‘Naturland’ organic standard as a reference. So far the outcomes have, however, been proven unsatisfactory. With the aim to better understand the reasons for these poor outcomes, a survey of forty households was conducted in a production forest in Rach Goc commune, Ngoc Hien District. We evaluated farmers’ perceptions on mangrove management, the drivers guiding shrimp farming, and whether there was a difference between participants and non-participants in a former ‘Naturland’ organic project. To complement the survey, a range of stakeholders involved in shrimp value chains were interviewed to better understand the terms and benefits of certification. The results of this survey suggested that, when applied to shrimp–mangrove farming systems in production forests in Ca Mau, ‘eco-certification’ and associated benefits are not very satisfactory. The survey results revealed that certified farms do not show significant differences to non-certified farms in terms of social and environmental benefits. As far as the implementation process was concerned, the survey results showed that a failure to integrate local farmers as participants consequently resulted in households becoming ‘objects’ for certification and not project partners with equal weight and power. It appears that rather than being a tool for improvement, ‘Naturland’ certification for shrimp–mangrove farming systems in Ca Mau’s production forests has become an end in itself.

Along with the urbanization, Da Nang is facing many challenges to become a modern metropolis, sustainable development. One of the major challenges is a growing number of conflicts related to land and objects’ land use. In this study, we collected relevant data and conducted a survey on three main groups related to the issue of land use in Son Tra District and Cam Le District. According to the study’s result, Da Nang City is having many land inconsistencies which can be turned into conflicts at different levels. Since then, this study presents a number of proposal to mitigate the conflicts in the use of land resources in order to improve their efficiency use with a point of view for the sustainable development at Da Nang City.

Silicon nanowires (Si NWs) were fabricated on Si (111) surfaces using both magnetron sputtering and thermal evaporation methods. Au thin layers were deposited using the electron-beam (e-beam) evaporation method and used as metal catalysts. The Au particles were formed by annealing at high temperature; their dimensions depended on the Au layer thickness and affected the formation and dimension of Si NWs. Field emission scanning electron microscopy (FESEM) was used to characterize the Si NWs. Photoluminescence (PL) measurement was conducted to demonstrate the quantum confinement effect of the Si NWs.

Worldwide, an estimated 35 % of mangrove forests have been lost between 1980 and 2005—among other reasons due to expansion of aquaculture production systems. In Vietnam, where the total mangrove area decreased from 269,150 ha in 1980 to 157,500 ha in 2000, regulation of such systems in the form of ‘mangrove-to-water surface ratio’ has had limited success to halt these losses. In this study, a survey of 40 Vietnamese households was conducted in mangrove production forests in Rach Goc commune, Ngoc Hien district, Ca Mau province to understand whether fixed limits on minimal mangrove coverage influence farmers’ decisions on mangrove protection. Results of the survey suggest that rural households greatly depend on the incomes generated from shrimp (and crab) farming but that they do not have a share in economic incentives from timber harvests due to lack of full ownership. A strong relationship between mangrove coverage and per pond area income was also revealed. Because farmers are not aware of applicable laws in terms of mangrove-to-water ratios, mangrove coverage tends to shift in favour of higher pond areas. Overall, the findings indicate that regulations in the form of universal mangrove-to-water ratios do not consider the realities of local households, nor are they economically or environmentally useful—rather, they appear to be arbitrary limitations that are not respected by affected communities. The findings question the efficiency of efforts put into stricter enforcement. Electronic supplementary material The online version of this article (doi:10.1186/s40064-016-2070-3) contains supplementary material, which is available to authorized users.

With the continuous advancements in molecular biology and modern medicine, organic synthesis has become vital to the support and extension of those discoveries. The isolations of new natural products allow for the understanding of their biological activities and therapeutic value. Organic synthesis is employed to aid in the determination of the relationship between structure and function of these natural products. The development of synthetic methodologies in the course of total syntheses is imperative for the expansion of this highly interdisciplinary field of science. In addition to the practical applications of total syntheses, the structural complexity of natural products represents a worthwhile challenge in itself. The pursuit of concise and efficient syntheses of complex molecules is both gratifying and enjoyable.