Choosing downscaling techniques is crucial in obtaining accurate and reliable climate change predictions, allowing for detailed impact assessments of climate change at regional and local scales. ...Traditional statistical methods are likely inefficient in downscaling precipitation data from multiple sources or complex data patterns, so using deep learning, a form of nonlinear models, could be a promising solution. In this study, we proposed to use deep learning models, the so‐called long short‐term memory and feedforward neural network methods, for precipitation downscaling for the Vietnamese Mekong Delta. Model performances were assessed for 2036–2065 period, using original climate projections from five climate models under the Coupled Model Intercomparison Project Phase 5, for two Representative Concentration Pathway scenarios (RCP 4.5 and RCP 8.5). The results exhibited that there were good correlations between the modelled and observed values of the testing and validating periods at two long‐term meteorological stations (Can Tho and Chau Doc). We then analysed extreme indices of precipitation, including the annual maximum wet day frequency (Prcp), 95th percentile of precipitation (P95p), maximum 5‐day consecutive rain (R5d), total number of wet days (Ptot), wet day precipitation (SDII) and annual maximum dry day frequency (Pcdd) to evaluate changes in extreme precipitation events. All the five models under the two scenarios predicted that precipitation would increase in the wet season (June–October) and decrease in the dry season (November–May) in the future compared to the present‐day scenario. On average, the means of multiannual wet season precipitation would increase by 20.4 and 25.4% at Can Tho and Chau Doc, respectively, but in the dry season, these values were projected to decrease by 10 and 5.3%. All the climate extreme indices would increase in the period of 2036–2065 in comparison to the baseline. Overall, the developed downscaling models can successfully reproduce historical rainfall patterns and downscale projected precipitation data.
Statistical downscaling of precipitation using machine learning of long short‐term memory and feedforward neural network.
Successful downscaling of precipitation was obtained from five global climate models for the Vietnamese Mekong Delta.
Increasing future precipitation in the wet season and decreasing in the dry season in both RCP 4.5 and RCP 8.5 scenarios.
Six extreme indices of precipitation were analysed with a robust trend of increased flooding and drought probability.
The outputs of statistical downscaling could be used for further basin assessments and beneficial for water resources management.
Macrolide-resistant Bordetella pertussis emerged in Vietnam during 2016-2017. Direct analyses of swab samples from 10 patients with pertussis revealed a macrolide-resistant mutation, A2047G, in the ...23S rRNA. We identified the MT104 genotype of macrolide-resistant B. pertussis (which is prevalent in mainland China) and its variants in these patients.
During 2015-2018, seven schools in rural Vietnam experienced diphtheria outbreaks. Multilocus sequence types were the same within schools but differed between schools. Low vaccine coverage and ...crowded dormitories might have contributed to the outbreaks. Authorities should consider administering routine vaccinations and booster doses for students entering the school system.
In this paper, we present a novel time-efficient tag identification protocol for active radio frequency identification (RFID) systems. Our protocol design is based on a conventional M-ary Detecting ...Tree (MDT) that divides contention tags into M subgroups and performs the identification in two phases: scanning and collecting. While the MDT protocol effectively eliminates redundant empty slots (i.e., slots without any tag responses), it requires two success slots (i.e., slots with exactly one tag's response) to identify one tag, raising concerns about potential identification delays. We introduce an innovative anti-collision protocol called Enhanced M-ary Detecting Tree (EMDT) to address this issue. The proposed EMDT switches from the scanning phase to the collecting phase when the estimated number of responding tags becomes smaller than a predefined threshold, which is found via theoretical analysis and has an optimal value of three. This adjustment allows the reader to typically require just one success slot for identifying each tag, thus significantly reducing the total time needed to identify all tags. The proposed phase-switching mechanism is backed by Zero-Estimation (ZE) for tag cardinality estimation and Manchester encoding for data transmission, both widely employed in RFID standards. Theoretical analysis and computer simulations are performed in different system settings, including ideal and non-ideal transmission channels, to validate the efficacy of the proposed protocol in comparison with conventional alternatives.
The objective of the present study was to investigate the toxicity of silver nanoparticles (Ag NPs)
in vitro. Silver ions (Ag+) have been used in medical treatments for decades whereas Ag NPs have ...been used in a variety of consumer products within recent years. This study was undertaken to compare the effect of well characterized, PVP-coated Ag NPs (69
nm
±
3
nm) and Ag+ in a human monocytic cell line (THP-1). Characterization of the Ag NPs was conducted in both stock suspension and cell media with or without serum and antibiotics. By using the flowcytometric annexin V/propidium iodide (PI) assay, both Ag NPs and Ag+ were shown to induce apoptosis and necrosis in THP-1 cells depending on dose and exposure time. Furthermore, the presence of apoptosis could be confirmed by the TUNEL method. A number of studies have implicated the production of reactive oxygen species (ROS) in cytotoxicity mediated by NPs. We used the fluorogenic probe, 2′,7′-dichlorofluorescein to assess the levels of intracellular ROS during exposure to Ag NPs and Ag+. A drastic increase in ROS levels could be detected after 6–24
h suggesting that oxidative stress is an important mediator of cytotoxicity caused by Ag NPs and Ag+.
With the growing demand for high-speed connectivity and global coverage in future 6G networks, free-space optics (FSO)-based aerospace integrated networks, incorporating low Earth orbit (LEO) ...satellites, high-altitude platforms (HAP), and unmanned aerial vehicles (UAV), have recently attracted research efforts worldwide. Nevertheless, critical challenges on FSO links include weather conditions, atmospheric turbulence, and pointing misalignment. This paper addresses the design of error-control protocols for reliable FSO-based aerospace backhaul networks, when multiple UAVs are deployed as flying base stations (BSs). Specifically, we introduce a design proposal of a cooperative hybrid automatic repeat request (C-HARQ)-based frame allocation mechanism (FAM)/rate adaptation. The design proposal guarantees the latency fairness constraints among multiple UAVs experiencing varying turbulence channel conditions. An analytical channel model for HAP-aided relaying LEO satellite to the emerging UAV-mounted BS FSO links is provided. Moreover, we develop a comprehensive analytical framework taking into account the imperfect channel state information (CSI) to assess system performance metrics, including throughput, average frame delay, and energy efficiency. Numerical results confirm the effectiveness of our design proposal by comparing it with the conventional approach without FAM for various turbulence channel conditions and quality of service (QoS) requirements. Additionally, we offer a design guideline for the proper selection of parameters that can be helpful for the practical design of reliable FSO-based aerospace backhaul networks. Finally, the theoretical results are verified by Monte-Carlo simulations, along with some in-depth discussions.
Rotavirus group A (RVA) is the most common cause of severe childhood diarrhea worldwide. The introduction of rotavirus vaccination programs has contributed to a reduction in hospitalizations and ...mortality caused by RVA. From 2016 to 2021, we conducted surveillance to monitor RVA prevalence and genotype distribution in Nam Dinh and Thua Thien Hue (TT Hue) provinces where a pilot Rotavin-M1 vaccine (Vietnam) implementation took place from 2017 to 2020. Out of 6626 stool samples, RVA was detected in 2164 (32.6%) by ELISA. RT-PCR using type-specific primers were used to determine the G and P genotypes of RVA-positive specimens. Whole genome sequences of a subset of 52 specimens randomly selected from 2016 to 2021 were mapped using next-generation sequencing. From 2016 to 2021, the G9, G3 and G8 strains dominated, with detected frequencies of 39%, 23%, and 19%, respectively; of which, the most common genotypes identified were G9P8, G3P8 and G8P8. G1 strains re-emerged in Nam Dinh and TT Hue (29.5% and 11.9%, respectively) from 2020 to 2021. G3 prevalence decreased from 74% to 20% in TT Hue and from 21% to 13% in Nam Dinh province between 2017 and 2021. The G3 strains consisted of 52% human typical G3 (hG3) and 47% equine-like G3 (eG3). Full genome analysis showed substantial diversity among the circulating G3 strains with different backgrounds relating to equine and feline viruses. G9 prevalence decreased sharply from 2016 to 2021 in both provinces. G8 strains peaked during 2019–2020 in Nam Dinh and TT Hue provinces (68% and 46%, respectively). Most G8 and G9 strains had no genetic differences over the surveillance period with very high nucleotide similarities of 99.2–99.9% and 99.1–99.7%, respectively. The G1 strains were not derived from the RVA vaccine. Changes in the genotype distribution and substantial diversity among circulating strains were detected throughout the surveillance period and differed between the two provinces. Determining vaccine effectiveness against circulating strains over time will be important to ensure that observed changes are due to natural secular variation and not from vaccine pressure.
•In Vietnam from 2016 to 2021, the G9 RVA genotype was the most frequently detected, followed by G3 (23.9%) and G8 (18.8%)•The circulating G3P8 genotypes were phylogenetically diverse with human and equine-like strains equally distributed.•The antigenic epitopes present on VP7 protein of G1, G3 and G9 strains differed considerably with vaccine strains.
Objective
To estimate the average treatment costs of pneumonia and meningitis among children under five years of age in a tertiary hospital in Hanoi, Vietnam from societal, health sector and ...household perspectives.
Methods
We used a cost‐of‐illness approach to identify cost categories to be included for different perspectives. A prospective survey was conducted among eligible patients to get detailed personal costing items.
Results
From the perspective of the health sector, the mean costs for treating a case of pneumonia and meningitis were USD 180 and USD 300, respectively. From the household's perspective, the average treatment costs were USD 272 for pneumonia and USD 534 for meningitis. When also including indirect costs, the average total treatment costs from the societal perspective were USD 318 for pneumonia and USD 727 for meningitis.
Conclusion
The study contributed to limited evidence on the high treatment costs of pneumonia and meningitis to the Vietnamese society, which is useful for a cost‐effectiveness analysis of Haemophilus influenzae type b vaccine or other relevant disease preventions. It also indicated a need to re‐evaluate the health insurance policy for children under 6 years old, so that the unnecessarily high out‐of‐pocket costs of these diseases are reduced.
Objectif
Estimer les coûts moyens de traitement de la pneumonie et de la méningite chez les enfants de moins de cinq ans dans un hôpital de soins tertiaires à Hanoi, Vietnam selon des perspectives sociétales, du secteur de la santé et des ménages.
Méthodes
Nous avons utilisé une approche du coût de la maladie pour identifier les catégories de coûts à inclure selon les différentes perspectives. Une enquête prospective a été menée chez des patients éligibles pour obtenir des éléments détaillés sur les coûts personnels.
Résultats
Du point de vue du secteur de la santé, les coûts moyens pour le traitement d'un cas de pneumonie et de méningite étaient de 180 et de 300 USD, respectivement. Du point de vue des ménages, les coûts moyens de traitement étaient de 272 USD pour une pneumonie et de 534 USD pour la méningite. Si l'on inclut également les coûts indirects, les coûts moyens totaux de traitement du point de vue sociétal étaient de 318 USD pour une pneumonie et de 727 USD pour la méningite.
Conclusion
L’étude a contribué à des preuves limitées sur les coûts élevés de traitement de la pneumonie et la méningite pour la société vietnamienne, ce qui est utile pour une analyse coût‐efficacité du vaccin contre Haemophilus influenzae de type b ou d'autres moyens de prévention des maladies concernées. Elle a également indiqué la nécessité de réévaluer la politique d'assurance‐santé pour les enfants de moins de 6 ans, de sorte que les coûts inutilement élevés et payés de la poche pour ces maladies soient réduits.
Objetivo
Calcular el coste medio de los tratamientos para la neumonía y la meningitis en niños menores de cinco años en un hospital terciario de Hanoi, Vietnam, desde las perspectivas social, sanitaria y del hogar.
Métodos
Hemos utilizado una aproximación al coste de la enfermedad para identificar las categorías de costes que debían de ser incluidas teniendo en cuenta las diferentes perspectivas. Se realizó un estudio prospectivo entre pacientes elegibles para obtener datos detallados sobre el coste de los diferentes ítems.
Resultados
Desde una perspectiva sanitaria, el coste medio de tratar un caso de neumonía y de meningitis era de USD 180 y USD 300, respectivamente. Desde la perspectiva del hogar, el coste medio del tratamiento era USD 272 para la neumonía y USD 534 para la meningitis. Al incluir los costes indirectos, el coste medio del tratamiento desde una perspectiva social era USD 318 para la neumonía y USD 727 para la meningitis.
Conclusión
El estudio ha contribuido, con una evidencia limitada, a mostrar los grandes costes del tratamiento de la neumonía y de la meningitis para la sociedad Vietnamita, lo cual es útil para el análisis coste‐efectivo de la vacuna contra Haemophilus influenzae tipo B u otros tipos de prevención relevantes para estas enfermedades. También indica una necesidad de reevaluar la política del seguro sanitario para niños menores de 6 años, de forma que los gastos de bolsillo innecesariamente altos para estas enfermedades se vean reducidos.
In some settings, rotavirus vaccines have been associated with a low-level risk of intussusception, the most common cause of bowel obstruction in infants. As Vietnam prepares to introduce rotavirus ...vaccine into the national immunization program, we sought to better characterize the epidemiology of recurrent intussusception. We enrolled children <2 years of age who were hospitalized for intussusception retrospectively from January 2013 through December 2014 and prospectively from January 2015 through December 2016 at 2 hospitals in Vietnam. We enrolled 2477 children. Nearly all children were successfully treated by enema with low surgery rate (1%). We found 10% of children (n = 254) experienced at least once recurrence (range: 1–6) and 57% of first recurrences happened within the first 12 weeks after treatment of the first episode. The median age at first intussusception was 13 months for children without a recurrent episode and 10 months for children with a recurrence. The symptoms of the recurrent cases were milder with less vomiting (67%), bloody stool (7%) and fever (10%) compared to the initial cases (p < 0.01). We found the rate of recurrences following enema reduction of intussusception to be similar to that reported from other countries. Due to the high rate of intussusception and recurrent episodes in Vietnam, a better understanding of the cause of recurrent intussusception will be critical in assessing intussusception cases after rotavirus introduction.
The frequency of typical and atypical Beijing strains of Mycobacterium tuberculosis was determined in the Netherlands; Vietnam; and Hong Kong Special Administrative Region, People's Republic of ...China. The strains' associations with drug resistance, M. bovis BCG vaccination, and patient characteristics were assessed. BCG vaccination may have positively selected the prevalent typical Beijing strains.
PDF
