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The global COVID-19 vaccine surplus:tackling expiring stockpiles

Infectious Diseases of Poverty 2023年第2期12卷 106-111页

作者： nguyen khoi quan nguyen Le My Anh Andrew W.Taylor-Robinson College of Health Sciences VinUniversityGia Lam DistrictHanoi100000Vietnam Faculty of Medicine Imperial College LondonLondonSW72AZUK Center for Global Health Perelman School of MedicineUniversity of PennsylvaniaPhiladelphiaPA19104USA

Background A global surplus of coronavirus disease 2019(COVID-19)vaccines exists as a result of difficulties in aligning the demand and supply for vaccine manufacturing and *** leaders have accelerated vaccine development,approval,production and distribution as a pragmatic approach to addressing the immediate public health challenges of the first two and a half years of the *** body The currently predominant,highly transmissible Omicron variant of severe acute respiratory syndrome coronavirus 2 has brought us closer to the threshold required to achieve herd immunity by greatly increasing rates of natural ***,in parallel with rising vaccination levels in industrialized nations,this indirectly reduces the need for mass vaccine *** concerns that contribute to low vaccination rates which persist in several other countries,particularly of the Global South,are vaccine hesitancy and unequal access to *** uncertainty fueled by fake news,misinformation,unfounded lay opinions and conspiracy theories has inevitably led to an erosion of public trust in *** To address the current mismatch between supply and demand of COVID-19 vaccines,there should be a focus on three principles:decelerating vaccine production,increasing distribution across communities,and optimizing cost-effectiveness of distribution *** down and switching from large-scale production to effectively‘made to order’is a feasible option,which should be commensurate with management *** and evidence-based data should be widely and freely disseminated to the public through multimedia channels to mitigate miscommunication and conspiracy *** of soon-to-expire stockpiles should be prioritized not only to enhance booster dose rollouts in adults but to expand immunization campaigns to children(especially those aged 5–11 years),subject to national *** research should ideally aim to de

关键词： COVID-19 SARS-CoV-2 Omicron Vaccination Immunization Vaccine surplus Vaccine hesitancy Vaccine reluctance Vaccine inequity

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Spatiotemporal Trend Analysis of Precipitation Extremes in Ho Chi Minh City, Vietnam During 1980–2017

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International Journal of Disaster Risk Science 2021年第1期12卷 131-146页

作者： nguyen Trong quan Dao nguyen khoi nguyen Xuan Hoan nguyen Ky Phung Thanh Duc Dang Faculty of Environmental and Food Engineering Nguyen Tat Thanh UniversityHo Chi Minh City 700000Vietnam Faculty of Environment University of ScienceHo Chi Minh City 700000Vietnam Vietnam National University Ho Chi Minh City 700000Vietnam Ho Chi Minh City University of Food Industry Ho Chi Minh City 700000Vietnam Institute for Computational Science and Technology Ho Chi Minh City 700000Vietnam Engineering Systems and Design Pillar Singapore University of Technology and DesignTampines 487372Singapore

In this study,the spatiotemporal variability of trends in extreme precipitation events in Ho Chi Minh City during the period 1980–2017 was analyzed based on several core extreme precipitation indices(Rx1 day,Rx5 day,CDD,CWD,R20 mm,R25 mm,R95 p,and SDII).The nonparametric Mann–Kendall and Sen’s slope methods were used to compute the statistical strength,stability,and magnitude of trends in annual rainfall,as well as the extreme precipitation *** found that 64%of the stations had statistically significant upward trends in yearly rainfall,with high magnitudes frequently observed in the northern and southern regions of the *** the extreme precipitation indices,only SDII and R25 mm showed dominantly significant ***,there were increasing trends in the frequency and duration at the southern and central regions of the city during the study ***,El Ni?o-Southern Oscillation and Pacific Decadal Oscillation positively correlated with the duration and negatively correlated with the intensity and frequency of extreme ***,water management plans should be adjusted appropriately to reduce the severe impacts of precipitation extremes on communities and ecosystems.

关键词： Spatiotemporal trend Extreme precipitation Extreme precipitation indices Ho Chi Minh City

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Evaluation of five gridded rainfall datasets in simulating streamflow in the upper Dong Nai river basin,Vietnam

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International Journal of Digital Earth 2019年第3期12卷 311-327页

作者： Pham Thi Thao Nhi Dao nguyen khoi nguyen Xuan Hoan Institute of Research and Development Duy Tan UniversityDa NangVietnam Institute for Computational Science and Technology Tan Hiep Chanh WardDistrict 12Ho Chi Minh CityVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh City227 Nguyen Van Cu StreetDistrict 5Ho Chi Minh CityVietnam Ho Chi Minh City University of Food Industry 140 Le Trong Tan StreetTan Phu DistrictHo Chi Minh CityVietnam

Rainfall data with an appropriate spatial resolution is a key input to hydrological ***,networks of rain gauges are often sparsely and unevenly distributed in large catchments,especially in developing ***-resolution rainfall datasets,such as the Asian Precipitation Highly Resolved Observational Data Integration Towards Evaluation of Water Resources(APHRODITE),the Climate Forecast System Reanalysis(CFSR),the Climatic Research Unit Time Series(CRUTS),the Global Precipitation Climatology Centre(GPCC)and the Tropical Rainfall Measuring Mission(TRMM),have become available to overcome such *** objective of this study was to evaluate the impacts of four land-based rainfall products(APHRODITE,CFSR,CRU-TS,and GPCC)and a satellite-based rainfall product(TRMM)on streamflow of the upper catchment of Tri An reservoir in Vietnam using the Hydrological Modeling System(HEC-HMS).In addition,the available rain gauges data were used for comparison *** indicates that the TRMM and GPCC data show their best match to rain gauges data in simulating the streamflow in the period 1999–***,the results indicate that the TRMM and GPCC data could be alternative solutions.

关键词： APHRODITE CFSR CRU-TS GPCC TRMM rainfall streamflow HEC-HMS model

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Assessment of Livelihood Vulnerability to Drought: A Case Study in Dak Nong Province, Vietnam

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International Journal of Disaster Risk Science 2019年第4期10卷 604-615页

作者： nguyen Thi Thanh Thao Dao nguyen khoi Tran Thanh Xuan Bernard Tychon Universite de Liege 6700 ArlonBelgium Institute for Environmental Science Engineeringand ManagementIndustrial University of Ho Chi Minh CityHo Chi Minh CityVietnam Institute of Research and Development Duy Tan UniversityDa NangVietnam Faculty of Environment University of ScienceVietnam National University Ho Chi Minh CityHo Chi Minh CityVietnam NTT Institute of Hi-Technology Nguyen Tat Thanh UniversityHo Chi Minh CityVietnam

In recent years,droughts have strongly affected the Central Highlands of Vietnam and have resulted in crop damage,yield decline,and serious water *** study investigated the livelihood vulnerability of five communities of farmers who are exposed to droughts in one of the more vulnerable regions of Vietnam—Dak Nong Province.A survey of 250 households was conducted in the five communities to collect data on the region’s sociodemographic profile,livelihood systems,social networks,health status,food and water security,drought conditions,and climate *** were aggregated using a livelihood vulnerability index and the IPCC vulnerability *** survey results indicate that quang Phu community is the most vulnerable of the study’s communities,followed by Nam N’dir,Dak Nang,Duc Xuyen,and Dak D’ro in descending order of *** availability and livelihood strategies are the most important variables in determining the vulnerability of the five surveyed *** order to reduce vulnerability to droughts,water management practices and livelihood diversification in farming and nonfarming activities are recommended for the study area.

关键词： Agricultural drought Livelihood vulnerability Vietnam Vulnerability indicators

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Thornthwaite moisture index and depth of suction change under current and future climate‒An Australian study

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1761-1775页

作者： Md Rajibul Karim Bikash Devkota Md Mizanur Rahman Hoang Bao khoi nguyen UniSA STEM University of South AustraliaMawson Lakes CampusMawson LakesSouth Australia5095Australia

Climate change is one of the major global challenges and it can have a significant influence on the behaviour and resilience of geotechnical *** changes in moisture content in soil lead to effective stress changes and can be accompanied by significant volume changes in reactive/expansive *** volume change leads to ground movement and can exert additional stresses on structures founded on or within a shallow depth of such *** change is likely to amplify the ground movement potential and the associated problems are likely to *** effect of atmospheric boundary interaction on soil behaviour has often been correlated to Thornthwaite moisture index(TMI).In this study,the long-term weather data and anticipated future projections for various emission scenarios were used to generate a series of TMI maps for *** changes in TMI were then correlated to the depth of suction change(H s),an important input in ground movement *** all climate scenarios considered,reductions in TMI and increases in H s values were observed.A hypothetical design scenario of a footing on expansive soil under current and future climate is *** is observed that a design that might be considered adequate under the current climate scenario,may fail under future scenarios and accommodations should be made in the design for such events.

关键词： Climate change Future prediction Thornthwaite moisture index(TMI) Characteristic surface movement Infrastructure resilience

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Predicting shear strength of slender beams without reinforcement using hybrid gradient boosting trees and optimization algorithms

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Frontiers of Structural and Civil Engineering 2022年第10期16卷 1267-1286页

作者： Thuy-Anh nguyen Hai-Bang LY Van quan TRAN Department of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam

Shear failure of slender reinforced concrete beams without stirrups has surely been a complicated occurrence that has proven challenging to adequately *** primary purpose of this work is to develop machine learning models capable of reliably predicting the shear strength of non-shear-reinforced slender beams(SB).A database encompassing 1118 experimental findings from the relevant literature was compiled,containing eight distinct *** Boosting(GB)technique was developed and evaluated in combination with three different optimization algorithms,namely Particle Swarm Optimization(PSO),Random Annealing Optimization(RA),and Simulated Annealing Optimization(SA).The findings suggested that GB-SA could deliver strong prediction results and effectively generalizes the connection between the input and output *** values and two-dimensional PDP analysis were then carried *** may use the findings in this work to define beam’s geometrical components and material used to achieve the desired shear strength of SB without reinforcement.

关键词： slender beam shear strength gradient boosting optimization algorithms

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Assessment of different machine learning techniques in predicting the compressive strength of self-compacting concrete

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Frontiers of Structural and Civil Engineering 2022年第7期16卷 928-945页

作者： Van quan TRAN Hai-Van Thi MAI Thuy-Anh nguyen Hai-Bang LY Faculty of Civil Engineering University of Transport TechnologyHanoi 100000Vietnam

The compressive strength of self-compacting concrete(SCC)needs to be determined during the construction design *** paper shows that the compressive strength of SCC(CS of SCC)can be successfully predicted from mix design and curing age by a machine learning(ML)technique named the Extreme Gradient Boosting(XGB)algorithm,including non-hybrid and hybrid *** ML techniques,such as Linear regression(LR),K-Nearest Neighbors(KNN),Support Vector Machine(SVM),Decision Trees(DTR),Random Forest(RF),Gradient Boosting(GB),and Artificial Neural Network using two training algorithms LBFGS and SGD(denoted as ANN_LBFGS and ANN_SGD),are also compared with the XGB ***,the hybrid models of eight ML techniques and Particle Swarm Optimization(PSO)are constructed to highlight the reliability and accuracy of SCC compressive strength prediction by the XGB_PSO hybrid *** highest number of SCC samples available in the literature is collected for building the ML *** with previously published works’performance,the proposed XGB method,both hybrid and non-hybrid models,is the most reliable and robust of the examined techniques,and is more accurate than existing ML methods(R2=0.9644,RMSE=4.7801,and MAE=3.4832).Therefore,the XGB model can be used as a practical tool for engineers in predicting the CS of SCC.

关键词： compressive strength self-compacting concrete machine learning techniques particle swarm optimization extreme gradient boosting

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Fabrication and Characterization of Multi-layer Heat Mirror with Photocatalytic Properties

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Chinese Physics Letters 2009年第11期26卷 152-155页

作者： Tran Le Tuan Tran Huu Chi nguyen Dac Ngoc Son Luu Minh Nam Hoang Dinh quan nguyen Department of Applied Physics College of Natural Science National University of He Chi Mirth City 227 Nguyen Van Cu District 5 Ward 4 He Chi Minh City Vietnam Department of Chemical Engineering College of Technology National University of He Chi Minh City 168 Ly Thuong Kiet District 10 Ho chi Minh City Vietnam

A novel TiO2（5）/TiO2（buffer）/Ti（4）/Ag（3）/Ti（2）/TiO2（1） multi-layer film coating with corning glass is designed and fabricated by a dc magnetron sputtering method as a renovation of the well-known TiO2/Ti/Ag/Ti/TiO2 system in order to obtain a heat mirror system with photocatalytic properties due to sufficient thickness of the Ti02 layer. The outer TiO2 layer is fabricated in two steps, possibly claimed as two layers TiO2（5） and TiO2（buuer）, among which TiO2（buffer） the 70-nm-thick layer deposited in poor oxygen effectively minimizes the oxidation toward its neighbor Ti（4） layer. The optimal total thickness of the TiO2（5） and TiO（buffer） di-layer is found to be 300nm to yield a highly photo-catalytic property of the film without affecting the optical properties considerably. This multi-layer film can transmit light of above 75-85% in the visible spectrum （380 ≤ λ≤ 760 nm） and reflect radiation of above 90% in the infrared spectrum （ λ≥760 nm）. Such multi-layer coatings are strongly recommended not only as promising transparent heat mirrors but also as photo-catalytic films for architectural window coatings.

关键词： Condensed matter: electrical magnetic and optical Surfaces interfaces and thin films Chemical physics and physical chemistry

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Research Power Manager for Ad Hoc on Demand Distance Vector Routing Protocol

Research Power Manager for Ad Hoc on Demand Distance Vector ...

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作者： nguyen DUONG quan 湖南大学

学位级别：硕士

随着人们对摆脱有线网络束缚、随时随地可以进行自由通信的渴望,近几年来无线网络通信得到了迅速的发展。人们可以通过配有无线接口的便携计算机或个人数字助理来实现移动中的通信。目前的移动通信大多需要有线基础设施(如基站)的支持... 详细信息

随着人们对摆脱有线网络束缚、随时随地可以进行自由通信的渴望,近几年来无线网络通信得到了迅速的发展。人们可以通过配有无线接口的便携计算机或个人数字助理来实现移动中的通信。目前的移动通信大多需要有线基础设施(如基站)的支持才能实现。为了能够在没有固定基站的地方进行通信,一种新的网络技术——MANET技术应运而生。Mobile ad hoc network-MANET(移动自组网络)不需要有线基础设备的支持,通过移动主机自由的组网实现通信。移动自组网络的出现推进了人们实现在任意环境下的自由通信的进程,同时它也为军事通信、灾难救助和临时通信提供了有效的解决方案。在现代化战场上,各种军事车辆之间、士兵之间、士兵与军事车辆之间都需要保持密切的联系,以实现统一指挥,协同作战。这是一种典型的移动自组织网络。这种网络据报道在最近的伊拉克战争中得到应用,效果不错。MANET已被认为是未来移动通信技术的核心组成部分之一,甚至有不少人认为MANET的思想将会把所有我们能想到的网络组合在一起,从而实现世界通信网络的大统一。MANET作为一种新的组网方式,具有网络的独立性、自动配置、动态变化的网络拓扑、有限的无线通信带宽、移动终端的局限性\有限的物理安全、网络的可扩展性不强、多跳路由存在单向的无线信道、特殊的信道共享方式、有限的主机能源等特点。MANET可以看作是移动通信和计算机网络的交叉。在移动自组网络中,使用计算机网络的分组交换机制,而不是电路交换机制。通信的主机一般是便携式计算机、个人数字助理等移动终端设备。MANET不同于目前因特网环境中的移动IP网络。在移动IP网络中,移动主机可以通过固定有线网络、无线链路和拨号线路等方式接入网络,而在移动自组网络中只存在无线链路一种连接方式。在移动IP网络中,移动主机通过相邻的基站等有线设施的支持才能通信,在基站和基站(代理和代理)之间均为有线网络,仍然使用因特网的传统路由协议。而移动自组网络没有这些设施的支持。此外,在移动IP网络中移动主机不具备路由功能,只是一个普通的通信终端。当移动主机从一个区移动到另一个区时并不改变网络拓扑结构,而MANET中移动主机的移动将会导致拓扑结构的改变。MANET的应用范围很广,总体上来说,它可以用于以下场合：没有有线通信设施的地方,如没有建立硬件通信设施或有线通信设施遭受破坏;需要分布式特性的网络通信环境;现有有线通信设施不足,需要临时快速建立一个通信网络的环境;作为生存性较强的后备网络。MANET技术因其可临时组网、快速发展、无控制中心、抗毁性强等特点。在军事领域中发挥着重要作用,随着移动通信和移动终端技术的高速发展,移动自组网技术不但在军事领域得到充分的发展,而且也引起了商用领域的极大兴趣,应用范围不断拓展。同时移动自组网互联趋势也带来新的问题。例如,在灾难恢复场景中,当地警察部队可能要与消防队员、军队及医务人员通过信息交流和共享来实现相互合作,而不需要考虑每个小组使用的特殊网络技术。这样的应用情景就需要一项技术,使不同行政领域的异构MANET之间实现端对端的通信。而其中一个关键问题就是路由协议互操作问题。关于这方面的研究并未得到太多研究团体的关注,本文在这里讨论了相关工作和下一步研究方向,可以为以后的相关研究提供一些依据。MANET与传统的蜂窝技术的根本区别在于移动节点之间的通信是在没有固定基础设施(例如基站或路由器)支持的条件下进行的,系统支持动态配置和动态数据流控制,所有的网络协议也都是分布式的。网络的组织和控制并不依赖于某些重要的节点,所有节点都是平等的。允许任一节点发生故障、离开或加入网络,另一方面,网络内的所有节点都必须在一定程度上相互合作以完成网络的功能。Ad Hoc网络技术是近年来十分活跃的研究领域。然而大多数研究都集中在多跳路由这个关键技术上。本文详细介绍了AODV协议的工作原理并优化了AODV的路由重建过程,重点分析了存在的题并提出了一些解决方案。AODV(按需距离向量协议Ad Hoc On Demand Distance Vector Routing)是一种重要的MANET按需路由协议,它只当源节点需要时才生成路由,AODV路由协议以其网络开销、算法复杂度等大部分性能指标优于其它同类而受到广泛关注,被认为是最有实用前景的Ad hoc网络路由协议之一,目前已被IETF标准化。AODV路由请求RREQ,路由应答RREP和路由错误RRER, AODV主要包含路由发现,路由维护和邻居管理等过程。当源节点需要发送数据而又没有到目的节点的有效路由时,就会启动一个路由发现过程：向网络广播一个路由请求分组(RREQ),当收到请求的中间节点或目的节点有一条足够新的路由到达目的地时,中间节点或者目

关键词： MANET 电源 AODV

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Ethyl acetate extract of Smilax glabra Roxb roots and its major active compound astilbin promote osteoblastogenesis in vitro by upregulating bone cell differentiation-associated genes

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Asian Pacific Journal of Tropical Biomedicine 2021年第12期11卷 553-560页

作者： Huyen T.T.nguyen Minh T.H.nguyen Thu X.nguyen quan M.Pham Ha X.nguyen Phuong T.M.nguyen University of Science and Technology of Hanoi Vietnam Academy of Science and TechnologyHanoiVietnam Institute of Biotechnology Vietnam Academy of Science and TechnologyHanoiVietnam Institute of Natural Products Chemistry Vietnam Academy of Science and TechnologyHanoiVietnam Graduate University of Science and Technology Vietnam Academy of Science and TechnologyHanoiVietnam

Objective:To investigate the osteoblastogenic activity of the ethyl acetate(EtOAc)extract of Smilax glabra Roxb roots and its major active compound ***:Astilbin was isolated from EtOAc extract using silica gel chromatography combined with fraction *** structure of astilbin was determined by analysis of the spectroscopic data in comparison with the *** method was used to detect the *** phosphatase(ALP)activity was determined by the spectrophotometric method at 405 nm using p-nitrophenyl phosphate as a *** deposition was stained with alizarin red-S,distained with cetylpyridium chloride,and quantified at 562 *** silico model for astilbin-ALP interaction was analyzed using AutoDock *** changes in expression of osteoblast differentiation related genes were determined using quantitative real-time ***:Both the EtOAc extract and astilbin had no toxicity toward osteoblast MC3T3-E1 cells at 5.0,10,25,and 50μg/*** 25μg/mL,they enhanced ALP activity and mineralization of osteoblasts up to 30%and 55%for the EtOAc extract and 22%and 41%for astilbin,*** docking analysis of astilbin-ALP interaction revealed Arg167,Asp320,His324,and His437 were key residues participating in hydrophobic interaction;meanwhile,His434 and Thr436 residues were involved in hydrogen bond formation in the active site of human tissue-nonspecific ***,the expression level of genes opn,col1,osx,and runx2 were up-regulated in astilbin treated samples with the fold changes as 2.2;3.7;4.1;2.3,respectively at 10μg/mL(P<0.05).Conclusions:The EtOAc extract and its major compound astilbin exhibit osteoblastogenic activity by up-regulating important markers for bone cell *** could be a new and promising osteogenic agent with dual actions for therapeutic applications.

关键词： Smilax glabra Roxb Astilbin Cytotoxicity Osteogenesis Osteoblast Ethyl acetate extract

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