Adherence to highly active antiretroviral therapy among people living with HIV and associated high-risk behaviours and clinical characteristics: A cross-sectional survey in Vietnam

Although Vietnam has promoted the utilisation of highly active antiretroviral therapy (HAART) towards HIV elimination targets, adherence to treatment has remained under-investigated. We aimed to describe high-risk behaviours and clinical characteristics by adherence status and to identify the factors associated with non-adherence. We included 426 people living with HIV (PLWH) currently or previously involved in HAART. Most participants were men (75.4%), young (33.6 years), with low income and low education levels. Non-adherent PLWH (11.5%) were more likely to have a larger number of sex partners (p-value = 0.053), sex without condom use (p-value = 0.007) and not receive result at hospital or voluntary test centre (p-value = 0.001). Multiple logistic regression analysis showed that demographic (education levels), sexual risk behaviours (multiple sex partners and sex without using condom) and clinical characteristics (time and facility at first time received HIV-positive result) were associated with HAART non-adherence. There are differences in associated factors between women (education levels and place of HIV testing) and men (multiple sex partners). Gender-specific programs, changing risky behaviours and reducing harms among PLWH may benefit adherence. We highlight the need to improve the quantity and quality of HIV/AIDS services in Vietnam, especially in pre- and post-test counselling, to achieve better HAART adherence, working towards ending AIDS in 2030. © The Author(s) 2021. **Please note that there are multiple authors for this article therefore only the name of the first 5 including Federation University Australia affiliate “Huy Nguyen” is provided in this record*

Electronic continuum states and far infrared absorption of InAs/GaAs quantum dots

The electronic continuum states of InAs/GaAs semiconductor quantum dots embedded in a GaAs/AlAs superlattice are theoretically investigated and the far infrared absorption spectra are calculated for a variety of structures and polarizations. The effect of a strong magnetic field applied parallel to the growth direction is also investigated. We predict that the flatness of the InAs/GaAs dots leads to a far infrared absorption which is almost insensitive to the magnetic field, in spite of the reorganization of the continuum into series of quasi-Landau states. We also predict that it is possible to design InAs/GaAs photoconductors which display very strong in-plane absorption.Comment: 8 pages, 10 figure

Wind induced vibration of stay cable bridge evaluation based on the operational accelerometers monitoring data and field testing

Wind induced vibrations are considering as one of the major concerns of the owner, the engineers and contractors of stay cable bridges. This paper presents in premier lieu the assessment of the vibration monitoring data from the pre-installed accelerometers on the longest cables of the Bach Dang bridge, Quang Ninh province. The identified cables natural frequencies based on the ambient vibration monitoring data were then compared to the taut string vibrating model calculation based on lift-off tension forces showing a good concordant. The enhanced damping of the cables stayed were then estimated and compared to the damping test results of another stay cables bridge recently performed in Vietnam with similar range of cables length. The damping prediction are quite in line with the damping test results and comparable also to those given in most of International Standard for stay cable. Finally, the identified natural frequencies and predicted intrinsic damping were used for an assessment of the wind induced vibration instability including the wind/rain induced vibration, wake galloping and vortex excitation

Wind induced vibration of stay cable bridge evaluation based on the operational accelerometers monitoring data and field testing

Wind induced vibrations are considering as one of the major concerns of the owner, the engineers and contractors of stay cable bridges. This paper presents in premier lieu the assessment of the vibration monitoring data from the pre-installed accelerometers on the longest cables of the Bach Dang bridge, Quang Ninh province. The identified cables natural frequencies based on the ambient vibration monitoring data were then compared to the taut string vibrating model calculation based on lift-off tension forces showing a good concordant. The enhanced damping of the cables stayed were then estimated and compared to the damping test results of another stay cables bridge recently performed in Vietnam with similar range of cables length. The damping prediction are quite in line with the damping test results and comparable also to those given in most of International Standard for stay cable. Finally, the identified natural frequencies and predicted intrinsic damping were used for an assessment of the wind induced vibration instability including the wind/rain induced vibration, wake galloping and vortex excitation

Effect of chromium substituted on structural and magnetic characterization lithium ferrite nanoparticles

In this work, we present a structural, morphology and magnetic study of the Li0.5Fe2.5-xCrxO4 spinel nanoparticles (x = 0, 0.5, 0.75, 1, and 1.25) with mean particle size of 20-30 nm prepared by sol-gel method. The lattice constants and the size of particle decrease with increasing Cr concentration. In these samples, the preference of Cr3+ and Li+ ions in the octahedral sites and a small degree of site-interchange between Li+ in the octahedral sites and Fe3+ in the tetrahedral sites were found which increases with increasing the Cr content. A decrease of magnetization due to the spin disorder in the surface layer of the particles was observed. The spontaneous magnetization at 5K suggests the Néel type of magnetic ordering in these samples. The magnetic coercivity is discussed in terms of particle size, morphology and chromium substitution. Keywords. Chromium substitution, sol-gel method, nanoparticles, lithium ferrite

Family of Hidden Markov Models and its applications to phylogenetics and metagenomics

textA Profile Hidden Markov Model (HMM) is a statistical model for representing a multiple sequence alignment (MSA). Profile HMMs are important tools for sequence homology detection and have been used in wide a range of bioinformatics applications including protein structure prediction, remote homology detection, and sequence alignment. Profile HMM methods result in accurate alignments on datasets with evolutionarily similar sequences; however, I will show that on datasets with evolutionarily divergent sequences, the accuracy of HMM-based methods degrade. My dissertation presents a new statistical model for representing an MSA by using a set of HMMs. The family of HMM (fHMM) approach uses multiple HMMs instead of a single HMM to represent an MSA. I present a new algorithm for sequence alignment using the fHMM technique. I show that using the fHMM technique for sequence alignment results in more accurate alignments than the single HMM approach. As sequence alignment is a fundamental step in many bioinformatics pipelines, improvements to sequence alignment result in improvements across many different fields. I show the applicability of fHMM to three specific problems: phylogenetic placement, taxonomic profiling and identification, and MSA estimation. In phylogenetic placement, the problem addressed is how to insert a query sequence into an existing tree. In taxonomic identification and profiling, the problems addressed are how to taxonomically classify a query sequence, and how to estimate a taxonomic profile on a set of sequences. Finally, both profile HMM and fHMM require a backbone MSA as input in order to align the query sequences. In MSA estimation, the problem addressed is how to estimate a ``de novo'' MSA without the use of an existing backbone alignment. For each problem, I present a software pipeline that implements the fHMM specifically for that domain: SEPP for phylogenetic placement, TIPP for taxonomic profiling and identification, and UPP for MSA estimation. I show that SEPP has improved accuracy compared to the single HMM approach. I also show that SEPP results in more accurate phylogenetic placements compared to existing placement methods, and SEPP is more computationally efficient, both in peak memory usage and running time. I show that TIPP more accurately classifies novel sequences compared to the single HMM approach, and TIPP estimates more accurate taxonomic profiles than leading methods on simulated metagenomic datasets. I show how UPP can estimate ``de novo'' alignments using fHMM. I present results that show UPP is more accurate and efficient than existing alignment methods, and estimates accurate alignments and trees on datasets containing both full-length and fragmentary sequences. Finally, I show that UPP can estimate a very accurate alignment on a dataset with 1,000,000 sequences in less than 2 days without the need of a supercomputer.Computer SciencesComputer Science

Factors Affecting the Perception of Happiness among Teachers in Vietnam

Vietnam is in the process of implementing education reforms in which teachers play a crucial role in determining success. This study aims to identify the main factors influencing the perception of happiness at work of Vietnamese teachers during the period of educational reform. In any period, teachers are always considered as being the force behind the success of education. Therefore, teachers' happiness is the most vital factor to be taken into consideration when educating students. Identifying the factors that affect teachers' happiness at work is the key to improving their teaching quality and quality of life. This study was conducted to investigate the factors affecting the perceived happiness of secondary school teachers in Vietnam today, thereby objectively assessing the emotional status of teachers in Vietnam in relation to the work they are doing. The results are as follows: 1) Teachers face a lot of pressure from many sides; 2) There is still a large percentage of teachers who do not really attach importance to the teaching profession; 3) State policies have not helped teachers feel secure in their professional activities; 4) Teacher capacity still needs to be greatly improved; 5) It is necessary to strengthen the connection between teachers, educational leaders, policy makers, school administrators and colleagues. This study uses descriptive statistics to present the research results. The survey was carried out in September 2021

Alloy effects in GaInN/GaN heterostructures

We show that the large band offsets between GaN and InN and the heavy carrier effective masses preclude the use of the Virtual Crystal Approximation to describe the electronic structure of Ga_(1-x)In_(x)N/GaN heterostructures while this approximation works very well for the Ga_(1-x)In_(x)As/GaAs heterostructures.Comment: submitted to Applied Physics Lette

Application of PCR-DGGE method for identification of nematode communities in pepper growing soil: Ứng dụng phương pháp PCR-DGGE để định danh cộng đồng tuyến trùng trong đất trồng hồ tiêu

Soil nematodes play an important role in indication for assessing soil environments and ecosystems. Previous studies of nematode community analyses based on molecular identification have shown to be useful for assessing soil environments. Here we applied PCR-DGGE method for molecular analysis of five soil nematode communities (designed as S1 to S5) collected from four provinces in Southeastern Vietnam (Binh Duong, Ba Ria Vung Tau, Binh Phuoc and Dong Nai) based on SSU gene. By sequencing DNA bands derived from S5 community sample, our data show 15 species containing soil nematode, other nematode and non-nematode (fungi) species. Genus Meloidogyne was found as abundant one. The genetic relationship of soil nematode species in S5 community were determined by Maximum Likelihood tree re-construction based on SSU gene. This molecular approach is applied for the first time in Vietnam for identification of soil nematode communities.Tuyến trùng đất đóng vai trò chỉ thị quan trọng trong công tác đánh giá môi trường và hệ sinh thái đất. Các nghiên cứu trước đây đã cho thấy lợi ích của việc phân tích cộng đồng tuyến trùng đất bằng định danh sinh học phân tử đối với việc đánh giá môi trường đất. Ở đây, chúng tôi ứng dụng phương pháp PCR-DGGE dựa trên gene SSU để phân tích năm (ký hiệu từ S1 đến S5) cộng đồng tuyến trùng đất thuộc các vùng trồng chuyên canh cây hồ tiêu ở miền nam Việt Nam (Bình Dương, Bà Rịa Vũng Tàu, Bình Phước và Đồng Nai). Bằng cách giải trình tự các vạch của mẫu tuyến trùng S5, kết quả cho thấy cộng đồng tuyến trùng này có 15 loài gồm nhóm tuyến trùng đất, nhóm các loại tuyến trùng khác và nhóm không phải tuyến trùng (nấm) và trong đó Meloidogyne là giống ưu thế. Mối quan hệ di truyền của các các loài tuyến trùng đất thuộc cộng đồng S5 được xác định bằng việc thiết lập cây phát sinh loài Maximum Likelihood dựa trên gene SSU. Đây là nghiên cứu đầu tiên ở Việt Nam sử dụng kỹ thuật PCR-DGGE để phân tích các cộng đồng tuyến trùng đất trồng hồ tiêu