38 research outputs found

    Interdisciplinary education in the context of protection of water resources: A case study in Vietnam

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    The incorporation of interdisciplinary education, a topic of significant global interest, is increasingly being recognized as a key aspect of educational innovation in Vietnam. This recognition extends to several fields, including STEM (Science, Technology, Engineering, and Mathematics) education.This research aims to design and implement a STEM situation associated with the context of water protection in Vietnam for 10th-grade students in which students mobilize the knowledge of Physics (specific gravity, Archimedes' principle) and Mathematics (volume) to design a salinometer. This device measures the salinity of the water. The research methodology is based on the observed increase in saline levels in the coastal regions of Vietnam in recent years, which has had a substantial impact on agriculture and the livelihoods of millions of people. This methodology aims to provide realistic scenarios for students to address and resolve these problems. A total of forty students in the 10th grade were involved in a teaching situation that consisted of five distinct phases. Forty 10th-grade students participated in a teaching situation conducted in five phases. The results showed that the situation helped students strengthen and connect their physics and mathematics knowledge, create a vibrant learning atmosphere, enhance communication, and develop problem-solving competency. Furthermore, the teaching situation also needs to be revised regarding the measurement practices of Vietnamese students. The situation contributes to educating students' awareness of current events, protecting Vietnamese water resources, and the importance of sustainable development. In addition, we can use the same teaching process as in this research to develop other STEM teaching situations

    Tri-axis convective accelerometer with closed-loop heat source

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    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

    Liquid pumping and mixing by PZT synthetic jet

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    In this paper, a PZT synthetic jet that can function as both an efficient pumping and mixing device is developed. Compare with the conventional design where the practice of controlling the internal flow is undertaken by microvalves structure, this approach promotes the durability and allows the device to work with different liquids at high Reynold number without losing of backflow from the diffuser, therefore provides efficient mixing. The pumping performance is applicable for commercialized counterparts while the homogeneous medium was obtained at downstream in the experiments, which was further confirmed by simulation. Notably, the chaotic mixing feature of the device is also applicable for immiscible liquids with the micro-droplet formation result at the outlet

    Autologous Transplantation of Adipose-Derived Stem Cells to Treat Acute Spinal Cord Injury: Evaluation of Clinical Signs, Mental Signs, and Quality of Life

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    BACKGROUD: Spinal cord injury (SCI) is damage that can cause a temporary or permanent change in spinal cord functions AIM: This work evaluates clinical signs, mental signs, and quality of life (QoL) after autologous adipose-derived stem cells (ADSCs) transplantation to treat acute spinal cord injury (SCI). MATERIAL AND METHODS: In this study, 47 SCI patients were recruited and divided into two groups: intervention and control. ADSCs were isolated and cultured under the cell culture quality control procedure. All patients in both groups underwent neurosurgery with or without ADSC transplantation. The recovery regarding neurological muscle, QoL, neurogenic bladder, and mental improvement was assessed after transplantation. RESULTS: All patients had improved in terms of motor function, bladder function, and daily living. No patients reported any side effect. MRI imaging showed significant changes in the lesion length of the spinal canal and the thickening of the spinal cord. Mental improvement was highest at six months after transplantation and lowest at one month after transplantation. The proportion of patients whose quality of life improved after treatment was 100%, while 80% of patients were satisfied with treatment outcomes. CONCLUSIONS: Thus, our data suggested that ADSCs transplantation was safe and effective for the treatment of SCI patients. Neurological muscle and neurogenic bladder were improved significantly after transplantation

    Morphological and molecular characteristics of Panax sp. (Araliaceae) from Phu Xai lai leng mountain, Nghe An province, Vietnam

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    Seven sterile and young specimens of Panax sp. were collected in Phu Xai Lai Leng silicat mountain, the highest mountain  peak in central Vietnam. Morphologically, they resemble P. stipuleanatus and P. bipinnatifidus. However, they have stipules and leaflets that are not bipinnatifid. The ITS-DNA sequences of Panax sp. from Phu Xai Lai Leng are identical and exhibit a close relationship with P. stipuleanatus from Tam Duong district, Lai Chau province with strong bootstrap support (98%). Noticeably, these two taxa  are different by 2 nucleotides. A collection of standard specimens including inflorescence, infructescence, flowers and ripe fruits of Panax from Phu Xai Lai Leng is needed to determine its taxonomic status.

    The global response: How cities and provinces around the globe tackled Covid-19 outbreaks in 2021

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    Background: Tackling the spread of COVID-19 remains a crucial part of ending the pandemic. Its highly contagious nature and constant evolution coupled with a relative lack of immunity make the virus difficult to control. For this, various strategies have been proposed and adopted including limiting contact, social isolation, vaccination, contact tracing, etc. However, given the heterogeneity in the enforcement of these strategies and constant fluctuations in the strictness levels of these strategies, it becomes challenging to assess the true impact of these strategies in controlling the spread of COVID-19.Methods: In the present study, we evaluated various transmission control measures that were imposed in 10 global urban cities and provinces in 2021 Bangkok, Gauteng, Ho Chi Minh City, Jakarta, London, Manila City, New Delhi, New York City, Singapore, and Tokyo.Findings: Based on our analysis, we herein propose the population-level Swiss cheese model for the failures and pit-falls in various strategies that each of these cities and provinces had. Furthermore, whilst all the evaluated cities and provinces took a different personalized approach to managing the pandemic, what remained common was dynamic enforcement and monitoring of breaches of each barrier of protection. The measures taken to reinforce the barriers were adjusted continuously based on the evolving epidemiological situation.Interpretation: How an individual city or province handled the pandemic profoundly affected and determined how the entire country handled the pandemic since the chain of transmission needs to be broken at the very grassroot level to achieve nationwide control

    Optimization in l1- norm for Sparse Recovery

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    This paper is about solving an optimization problem for a sparse solution. Given a matrix A and a vector b, the optimization problem is to solve the linear equation Ax = b for x. The problem can be represented as a minimization problem where we minimize the norm of x subject to Ax = b. By using L0- regularization, defined as the number of non-zero components, the problem becomes an NP-hard problem. Therefore we do a convex relaxation by using the L1- norm. With this relaxation we are able to find a sparse solution, a solution with few non-zero entries. The advantage with sparse vectors is that the computations take less time. Another advantage is that sparse vectors require less space when being stored, since we only need to know the position and the value of the entries. The problem is used in Compressed Sensing and in many other applications. Compressed Sensing is about representing signals by using few non-zero coefficients in a basis. For the system we are solving to have sparse recovery, it requires conditions such as the Null Space Condition, the Spark, the Restricted Isometry Property and the Coherence. There are many methods for solving this problem, and in this paper Basis Pursuit and Greedy algorithms will be presented
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