To assess the role of in-flight transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we investigated a cluster of cases among passengers on a 10-hour commercial flight. ...Affected persons were passengers, crew, and their close contacts. We traced 217 passengers and crew to their final destinations and interviewed, tested, and quarantined them. Among the 16 persons in whom SARS-CoV-2 infection was detected, 12 (75%) were passengers seated in business class along with the only symptomatic person (attack rate 62%). Seating proximity was strongly associated with increased infection risk (risk ratio 7.3, 95% CI 1.2-46.2). We found no strong evidence supporting alternative transmission scenarios. In-flight transmission that probably originated from 1 symptomatic passenger caused a large cluster of cases during a long flight. Guidelines for preventing SARS-CoV-2 infection among air passengers should consider individual passengers' risk for infection, the number of passengers traveling, and flight duration.
The COVID-19 pandemic is spreading fast globally. Vietnam's strict containment measures have significantly reduced the spread of the epidemic in the country. This was achieved through the use of ...emergency control measures in the epidemic areas and integration of resources from multiple sectors including health, mass media, transportation, education, public affairs, and defense. This paper reviews and shares specific measures for successful prevention and control of COVID-19 in Vietnam, which could provide useful learning for other countries.
Supervised contrastive learning (SCL) has recently emerged as an alternative to conventional machine learning and deep neural networks. In this study, we propose an SCL model with data augmentation ...techniques using phase-resolved partial discharge (PRPD) in gas-insulated switchgear (GIS). To increase the fault data for training, we employ Gaussian noise adding, Gaussian noise scaling, random cropping, and phase shifting for supervised contrastive loss. The performance of the proposed SCL was verified by four types of faults in the GIS and on-site noise using an on-line ultra-high-frequency (UHF) partial discharge (PD) monitoring system. The experimental results show that the proposed SCL achieves a classification accuracy of 97.28% and outperforms the other algorithms, including support vector machines (SVM), multilayer perceptron (MLP), and convolution neural networks (CNNs) in terms of classification accuracy, by 6.8%, 4.28%, 2.04%, respectively.
► We introduce a hysteresis functional link artificial neural network (HFLANN) structure to approximate the dynamics of a shape memory alloy actuator. ► HFLANN includes hysteresis operator and ...functional link artificial neural network. ► A model predictive controller based on the HFLANN is newly derived. ► The effectiveness of the proposed controller is verified through the simulation and experiments.
In this paper, a modified Hysteresis Functional Link Artificial Neural Network (HFLANN) is proposed to identify and control a Shape Memory Alloy (SMA) actuator, which has an inherent hysteresis phenomenon. In this structure, a hysteresis operator combined with the Functional Link Artificial Neural Network (FLANN) to employ the hysteresis phenomenon and the dynamic of the SMA actuator. The hysteresis operator is introduced to capture the SMA hysteresis. And the FLANN is employed to approximate the dynamic of the system. In identification problem, the FLANN parameters are trained by Particle Swarm Optimization technique. For control problem, a Model Predictive Controller based HFLANN is derived to control the system. The identification results show that the HFLANN can employ for the SMA dynamic. The simulation and experimental results demonstrated the effectiveness of the proposed algorithm. The SMA hysteresis phenomenon is compensated completely by proposed controller.
Approaching a child with dyspnea, coughing, and wheezing, doctors must consider a foreign body in the respiratory tract, and bronchoscopy should be performed. This report described a child having ...sunflower seed aspiration late‐ and misdiagnosed as pneumonia. He failed with antibiotics therapy. The patient underwent a bronchoscopy, and then the seed was found and entirely removed.
If a child has dyspnea, coughing, and wheezing, it is important to evaluate the possibility of foreign body aspiration, such as sunflower seed. If a foreign agent is present, bronchoscopy is an effective method for removing foreign objects.
High and sustainable growth of gross domestic product with stable inflation is one of the objectives of the most macroeconomic policies both in the world and in Vietnam. Therefore, price stability ...plays a vital role in assuring GDP growth. In order to stabilize prices, fiscal and monetary policies need to be appropriately managed. The aim of this study is to assess the impact of the monetary and fiscal policies on inflation in Vietnam during the period from 1997 to 2020. This study has applied the vector autoregression (VAR) model along with data gathered from the World Bank and General Statistics Office of Vietnam. The research results indicate that Vietnam’s inflation is positively influenced by a fiscal deficit (2.943), money supply (2.672), government expenditure (8.347), and interest rate (3.187). Among the factors, government expenditure has the biggest influence on inflation. Besides, trade openness (–0.311) also influences inflation, but the effect is negative and negligible. Finally, the policy implications are focused on coordinating fiscal and monetary policies maintaining a moderate level of inflation for economic growth.
AcknowledgmentThis article is funded from the funding source of the research: “Solutions to deal with the risk of financial instability from support packages to fight economic recession caused by the covid-19 pandemic” with code B2022-MHN-02 by Vietnam Misnistry of Education and Training.
The rolling bearing was an important part of the mining machine. Once the damage and maintenance was difficult, it will seriously affect the working efficiency of the mining machine.Based on the ...reliability analysis project of a coal mining machine, the lubrication performance of the output bearing of rocker arm was studied.Of thin seam coal winning machine developed by the project team get force curve of coal winning machine load simulator, based on the theory of Hertz contact mechanics study of cylindrical roller bearing contact state of low speed and heavy loading, on the basis of the contact behavior simulation, add the bearing oil film, through the establishment of bearing hydrodynamic lubrication theory and fluid-structure coupled model of oil film were analyzed, and the oil film thickness is obtained by analyzing the results of processing, the oil film pressure, film velocity and changes of the bearing parts contact.The fluid-solid coupling method is applied to the contact analysis of low-speed heavy-duty bearing, which provides a new method to study the contact problem of coal mining machine bearing.
International air travel plays an important role in the global spread of SARS-CoV-2, and tracing of close contacts is an integral part of the public health response to COVID-19. We aimed to assess ...the timeliness of contact tracing among airline passengers arriving in Vietnam on flights containing COVID-19 cases and investigated factors associated with timeliness of contact tracing.
We included data from 2228 passengers on 22 incoming flights between 2 and 19 March 2020. Contact tracing duration was assessed separately for the time between the date of index case confirmation and date of contact tracing initiation (interval I), and the date of contact tracing initiation and completion (interval II). We used log-rank tests and multivariable Poisson regression models to identify factors associated with timeliness.
The median duration of interval I and interval II was one (IQR: 1-2) and 3 days (IQR: 2-5), respectively. The contact tracing duration was shorter for passengers from flights where the index case was identified through mandatory testing directly upon arrival (median = 4; IQR: 3-5) compared to flights with index case detection through self-presentation at health facilities after arrival (median = 7; IQR: 5-8) (p-value = 0.018). Cumulative hazards for successful tracing were higher for Vietnamese nationals compared to non-Vietnamese nationals (p < 0.001).
Contact tracing among flight passengers in the early stage of the COVID-19 epidemic in Vietnam was timely though delays occurred on high workload days. Mandatory SARS-CoV-2 testing at arrival may reduce contact tracing duration and should be considered as an integrated screening tool for flight passengers from high-risk areas when entering low-transmission settings with limited contact tracing capacity. We recommend a standardized risk-based contact tracing approach for flight passengers during the ongoing COVID-19 epidemic.
The article evaluates the impact of income diversification on business performance of Vietnamese commercial banks in the period 2010-2020. The study collected data from from the financial statements ...of 29 commercial banks listed on both the Ho Chi Minh stock exchange and the Hanoi stock exchange in the period 2010-2020 from the FiinPro Database. GMM regression method is used to analyze the impact of income diversification on the business performance of Vietnamese commercial banks. The analysis results show that the business performance of commercial banks is influenced by many factors, the most influential factors are income diversification, the scale of credit activities, and the efficiency of management physical. Based on empirical results, the study proposes some recommendations to help banks improve businessperformance.
The importation of SARS-CoV-2 through air travel poses substantial risks to generate new COVID-19 outbreaks. Timely contact tracing is particularly crucial to limit onwards transmission in settings ...without established community transmission.
We conducted an in-depth analysis of the response to a big flight-associated COVID-19 outbreak in Vietnam in March 2020 that involved contact tracing, systematic testing and strict quarantine up to third generation contacts.
183 primary contacts from the flight as well as 1000 secondary and 311 third generation contacts were traced, tested, and quarantined across 15 provinces across Vietnam. The protracted confirmation of the index case at 3 days and 19 h after arrival resulted in isolation/quarantine delays of 6.8 days (IQR 6.3–6.8) and 5.8 days (IQR 5.8–7.0) for primary and secondary cases, respectively, which generated 84.0 and 26.4 person-days of community exposure from primary and secondary cases, respectively. Nevertheless, only 5 secondary cases occurred.
A large flight-related COVID-19 cluster was successfully contained through timely, systematic and comprehensive public health responses despite delayed index case identification. Multiagency collaboration and pre-established mechanisms are crucial for low and middle income countries like Vietnam to limit community transmission after COVID-19 importation through air travel.
•Successful control of large flight-imported COVID-19 outbreaks is possible.•Delayed index case confirmation complicates response measures.•A combination of contact tracing, systematic testing and quarantine is key.•Mandatory testing at arrival might be justified for certain settings.•A whole-of-government approach and pre-established protocols are important.
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