25 research outputs found
Investigation on the effect of cross beams in single span bridges under dynamic aspect by using finite element method
In the 1980s and 1990s, most bridges in Vietnam employed simple beam for short-span river crossings that did not need navigation and mainly used the reinforced concrete T-beams or pre-stressed concrete. While the T-frame structure that has hang single span is widely applied for rivers that require navigation...The single girder is a basic span made of pre-stressed reinforced concrete T or I cross section, with spacing ranging from 2.2m to 2.6m, and the absence of diaphragms was a common feature of bridges built during this time period. All horizontal crashes almost have happened on the spans that did not have diaphragms. As a result, the impact force is concentrated mostly on the lateral girders, leading to total damage. Thus, researches to evaluate the effect of diaphragms in the distribution of horizontal impact forces as well as minimizing the damage in the span structures are crucial. This study focuses on simulating and studying the influence of the number and position of the diaphragms in terms of stress, deformation and damage when a collision occurs in order to propose additional and repair solutions to enhance the horizontal resistance of span
Identify aerodynamic derivatives of the airplane attitude channel using a spiking neural network
The paper proposes a method for identifying aerodynamic coefficient derivatives of aircraft attitude channel using spiking neural network (SNN) and Gauss-Newton algorithm based on data obtained from actual flights. Using SNN combination with Gauss-Newton iterative calculation algorithm allows the identification of aerodynamic coefficient derivatives in a nonlinear model for aerodynamic parameters with higher accuracy and faster calculation time. The paper proposes an algorithm to train the SNN multi-layer network by Normalized Spiking Error Back Propagation (NSEBP), in which, in the forward propagation period, the time of output spikes is calculating by solving quadratic equations instead of detection by traditional methods. The phase of propagation of errors backward uses the step-by-step calculation instead of the conventional gradient calculation method. The identification results are compared with the results when using the RBN network to prove the algorithm efficienc
A Systematic Assessment of Greening Interventions for Developing Best Practices for Urban Heat Mitigation—The Case of Huế, Vietnam
The health of urban populations is increasingly at risk due to the amplification and chronification of urban heat stress by climate change. This is particularly true for urban environments in humid tropical climates, including many cities in Southeast Asia. It is also in these locations where increasing climatic risks may be exacerbated by urban growth, underscoring the need to develop effective mitigation strategies for strengthening urban resilience and supporting climate change adaptation. Conservation and widespread implementation of green infrastructure (GI) are regarded as one means to counter heat as a public health threat. However, for lower-income countries across Southeast Asia, such as Vietnam, knowledge gaps remain with respect to the effectiveness of greening interventions for heat mitigation. To address this gap, in the context of urban expansion in the humid tropical city of Huế, Vietnam, diurnal cooling potential and regulation of outdoor thermal comfort (OTC) within a wide, shallow street canyon were systematically assessed for selected elements of GI along a quantitative and qualitative dimension using ENVI-met. Tree-based interventions were found to be most effective, potentially decreasing UTCI by −1.9 K at the domain level. Although lower in magnitude, green verges and green facades were also found to contribute to OTC, with green verges decreasing UTCI by up to −1.7 K and green facades by up to −1.4 K locally. Potential synergistic cooling impacts were identified through a combination of GI elements. However, no scenario was found to decrease heat stress to zero or moderate levels. Substantially reducing heat stress may thus require further measures and a closer consideration of local morphological characteristics.This research was funded by the German Federal Ministry of Education and Research, grant number 01LE1910A1, and by the CLEARING HOUSE (Collaborative Learning in Research, Information-Sharing and Governance on How Urban Tree-Based Solutions Support Sino-European Urban Futures) Horizon 2020 project, grant number 821242.German Federal Ministry of Education and ResearchCLEARING HOUSEPeer Reviewe
PERCEPTIONS OF ENGLISH-MAJORED STUDENTS IN THE HIGH-QUALITY PROGRAM AT CAN THO UNIVERSITY TOWARD LEARNING ENGLISH THROUGH WATCHING MOVIES
This descriptive study aims to answer three main research questions, namely 1) What are the perceptions of English-majored students regarding the impact of watching English movies on their learning motivation?, 2) What are their perceptions of the impact of watching English movies on their language development?, and 3) What challenges do the students encounter when learning English through watching movies? In order to address these key questions, the data collected from 175 freshmen and juniors majoring in English Studies of the High-Quality Program at Can Tho University through a 5-point Likert scale questionnaire were quantitatively analyzed. The statistical analysis of the gathered data revealed that all the study participants strongly agreed with the positive impacts of watching English movies on their motivations to learn the target language as well as on their language development. Despite these positive effects, the students also admitted that they inevitably encountered several challenges while learning English through movie-watching, particularly in terms of rapid speech, extensive use of slang, and figurative language in English movies. Based on these research outcomes, possible implications have been further discussed for the effective use of movies in EFL classrooms to support the students’ learning process. Article visualizations
Ureaplasma urealyticum and Mycoplasma genitalium detection and sperm quality: A cross-sectional study in Vietnam
Background: Ureaplasma urealyticum (U. urealyticum) and Mycoplasma genitalium (M. genitalium) may colonize the male genital tract. However, the negative effects of these bacteria on overall sperm quality, including semen pH, sperm concentration, motility, morphology, and total sperm count remain unclear.
Objective: This study aimed to determine the presence of genital U. urealyticum and M. genitalium in semen and evaluate the effect of these organisms on sperm quality.
Materials and Methods: A cross-sectional study was conducted on 380 men from infertile couples at a tertiary university hospital from July 2017 to June 2018. Semen quality was analyzed according to the World Health Organization 2010 standard, and U. urealyticum and M. genitalium were detected in the semen samples using polymerase chain reaction.
Results: 338 men (88.9%) presented with at least one abnormal semen parameter. The detection rates of U. urealyticum and M. genitalium were 16.05% and 0.79%, respectively. There was no significant difference between the Ureaplasma-positive group and the Ureaplasma-negative group in terms of sperm characteristics. Sperm motility and sperm vitality in the Mycoplasma-positive group were much lower than those in the Mycoplasma-negative group (p = 0.02 and p < 0.001, respectively).
Conclusion: The presence of U. urealyticum in the semen of infertile men did not affect the sperm characteristics. Although the positive rate of M. genitalium was low, colonization by these bacteria was more likely to negatively affect sperm quality.
Key words: Ureaplasma urealyticum, Mycoplasma genitalium, Infertility, Spermatozoa
Assessing status and habitat of siamese fireback (Lophura diardi) by using camera trap in Lo Go-Xa Mat National Park, Vietnam
Siamese fireback, Lophura diardi, belonging to Galliformes is at risk due to habitat loss and hunting, which are main challenges to conservation of the species. In order to provide scientific information to conserve the L. diardi, we implemented a camera-trap survey in Lo Go-Xa Mat National Park from 2017 to 2018. Occupancy and Poisson regression models were used to investigate presence of the species and potential factors influencing the occurrence of the species in the study area. Our results showed that the probability of occurrence of the species at locations within the park was high at 0.84 (0.69–0.92) and detection probability was relative low at 0.19 (0.16–0.23). The best models consistently suggested that the abundance of the species was high in closed canopy forest cover (β = 0.41), but appeared to be notably lower in areas far away from the ranger stations (β = -0.25) and in places with high frequency of human (β = -0.22). This research provided the first quantitative information of status and potential factors influencing occurrence of the L. diardi in the park, which is an essential data for developing practical actions to protect the species and monitoring program in the future for the park.        Â
An Outbreak of Severe Infections with Community-Acquired MRSA Carrying the Panton-Valentine Leukocidin Following Vaccination
Background: Infections with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) are emerging
worldwide. We investigated an outbreak of severe CA-MRSA infections in children following out-patient vaccination.
Methods and Findings: We carried out a field investigation after adverse events following immunization (AEFI) were reported. We reviewed the clinical data from all cases. S. aureus recovered from skin infections and from nasal and throat swabs were analyzed by pulse-field gel electrophoresis, multi locus sequence typing, PCR and microarray. In May 2006, nine children presented with AEFI, ranging from fatal toxic shock syndrome, necrotizing soft tissue infection, purulent abscesses, to fever
with rash. All had received a vaccination injection in different health centres in one District of Ho Chi Minh City. Eight children had been vaccinated by the same health care worker (HCW). Deficiencies in vaccine quality, storage practices, or preparation and delivery were not found. Infection control practices were insufficient. CA-MRSA was cultured in four children and from nasal and throat swabs from the HCW. Strains from children and HCW were indistinguishable. All carried the Panton-Valentine leukocidine (PVL), the staphylococcal enterotoxin B gene, the gene complex for staphylococcal-cassette-chromosome mec type V, and were sequence type 59. Strain HCM3A is epidemiologically unrelated to a strain of ST59 prevalent in the USA, althoughthey belong to the same lineage.
Conclusions. We describe an outbreak of infections with CA-MRSA in children, transmitted by an asymptomatic colonized HCW during immunization injection. Consistent adherence to injection practice guidelines is needed to prevent CA-MRSA transmission in both in- and outpatient settings
One health, une seule santé
One Health, « Une seule santé », est une stratégie mondiale visant à développer les collaborations interdisciplinaires pour la santé humaine, animale et environnementale. Elle promeut une approche intégrée, systémique et unifiée de la santé aux échelles locale, nationale et mondiale, afin de mieux affronter les maladies émergentes à risque pandémique, mais aussi s'adapter aux impacts environnementaux présents et futurs. Bien que ce mouvement s’étende, la littérature en français reste rare. Traduit de l’anglais, coordonné par d’éminents épidémiologistes et s'appuyant sur un large panel d' approches scientifiques rarement réunies autour de la santé, cet ouvrage retrace les origines du concept et présente un contenu pratique sur les outils méthodologiques, la collecte de données, les techniques de surveillance et les plans d’étude. Il combine recherche et pratique en un seul volume et constitue un ouvrage de référence unique pour la santé mondiale
Structure-Based Discovery of ABCG2 Inhibitors: A Homology Protein-Based Pharmacophore Modeling and Molecular Docking Approach
ABCG2 is an ABC membrane protein reverse transport pump, which removes toxic substances such as medicines out of cells. As a result, drug bioavailability is an unexpected change and negatively influences the ADMET (absorption, distribution, metabolism, excretion, and toxicity), leading to multi-drug resistance (MDR). Currently, in spite of promising studies, screening for ABCG2 inhibitors showed modest results. The aim of this study was to search for small molecules that could inhibit the ABCG2 pump. We first used the WISS MODEL automatic server to build up ABCG2 homology protein from 655 amino acids. Pharmacophore models, which were con-structed based on strong ABCG2 inhibitors (IC50 < 1 μM), consist of two hydrophobic (Hyd) groups, two hydrogen bonding acceptors (Acc2), and an aromatic or conjugated ring (Aro|PiR). Using molecular docking method, 714 substances from the DrugBank and 837 substances from the TCM with potential to inhibit the ABCG2 were obtained. These chemicals maybe favor synthesized or extracted and bioactivity testing
A rare case of overlapping thoracic outlet syndrome attributed to an anatomical variation in the anterior scalene muscle: Diagnostic challenges and treatment approaches
Mixed thoracic outlet syndrome, which compresses arteries and nerves, is a rare disorder. Mixed thoracic outlet syndrome due to anatomical abnormalities of the anterior scalene muscle is even more sporadic. We report a case of mixed thoracic outlet syndrome in a patient with no history of trauma or vigorous exercise. We reviewed the medical literature, emphasizing the clinical role and the role of diagnostic imaging methods in a sequential approach to this syndrome