36 research outputs found
STRUCTURAL, VIBRATIONAL, OPTICAL, AND MAGNETIC PROPERTIES OF 0-3 TYPE PARTICULATE PbTiO3-NiFe2O4 COMPOSITES
We synthesized 0-3 type (1-x)PbTiO3-xNiFe2O4 (x = 0.0-0.5) multiferroic composites with two independently crystallized parent phases by the sol-gel method. Structural, surface morphology, vibrational, optical, and magnetic characteristics were investigated by X-ray diffraction (XRD), SEM, Raman scattering, UV-vis absorption, and magnetization (M-H) measurements, respectively. The XRD result showed that the lattice parameter a of the PbTiO3 (PTO) phase decreased while lattice parameter c increased after compositing, leading to a decrease in the tetragonal ratio c/a. SEM images indicated that the NiFe2O4 (NFO) crystals that crystallized later are small and adhere to the surface of the large PTO particles. The strong cohesion between the two components was also revealed by the gradual shift of the Raman peaks to the lower wavelength and the reduction of the Raman intensity as the NFO content increased. The UV-vis absorption result showed the co-absorption spectra of the parent phases in the composites. Magnetization curves presented a sharp increase in saturation magnetization MS with NFO content from 0.014 emu/g for the PTO sample to 14.360 emu/g for the composite containing 50 mol% NFO. This study indicates an effective method in the search for multilayer composites
STUDENTS' PERCEPTION OF THE INFLUENCE OF INTONATION IN ENGLISH ON CONVEYING THE MEANING OF SPEECH IN COMMUNICATION
In communication, intonation plays an important role in conveying the meaning of a speech. In this article, we study students' perception of the influence of intonation in conveying the meaning of speech in communication to propose solutions to help students overcome intonation errors when communicating, as well as, help teachers have appropriate intonation teaching methods. Our data and analysis are based on research documents, surveys, and in-depth interviews with students. According to the study results, most students are well aware of the importance of intonation and of the factors affecting intonation, and they are also aware of the causes of intonation errors. However, students do not apply their knowledge of intonation to speech, they stop at the cognitive level. The study indicates that students often make intonation mistakes in Tag-question, Wh-question, and Imperative sentence in communication. Article visualizations
Investigation of Sodium Manganese Oxide Nanowires Synthesized by Hydrothermal Method for Alkaline Ion Battery
Sodium Manganese Oxide (NaxMnO2) has attracted much attention as cathode materials for alkaline ion battery due to the ability of fast charge and discharge ion Na+, in particular in nanoscale. We report on the synthesis of NaxMnO2 nanowires via hydrothermal synthesis route from Mn2O3 and NaOH solution. The morphological observation indicates that the obtained Na0.44MnO2 nanowires with diameters of about 20-30 nm, length up to several micrometers were formed by this process. The electrochemical properties of fabricated materials were investigated by means of cyclic voltammetry technique and show that Sodium Manganese Oxide (NaxMnO2) is a promising material in the field of research and fabrication alkaline ion battery
Performance of Sampling/Resampling-based Particle Filters Applied to Non-Linear Problems
In this work, we propose a wireless body area sensor network (WBASN) to monitor patient position. Localization and tracking are enhanced by improving the effect of the received signal strength (RSS) variation. First, we propose a modified particle filter (PF) that adjusts resampling parameters for the Kullback-Leibler distance (KLD)-resampling algorithm to ameliorate the effect of RSS variation by generating a sample set near the high-likelihood region. The key issue of this method is to use a resampling parameter lower bound for reducing both the root mean square error (RMSE) and the mean number of particles used. To determine this lower bound, an optimal algorithm is proposed based on the maximum RMSE between the proposed algorithm and the KLD-resampling algorithm or based on the maximum mean number of particles used of these algorithms. Finally, PFs based on KLD-sampling and KLD-resampling are proposed to minimize the efficient number of particles and to reduce the estimation error compared to traditional algorithms
Can a Short Food Supply Chain Create Sustainable Benefits for Small Farmers in Developing Countries? An Exploratory Study of Vietnam
A number of studies have indicated that short food supply chains could create economic, social, and environmental benefits, but most of those chains were implemented in developed countries. This research aims to find out the characteristics of short food supply chains and their benefits to small farmers in Vietnam, which is a developing country, based on the survey results from 338 small farmers in the third quarter of 2020, with the support of Stata 14 software. The results showed that the short food supply chains in the survey sample in Vietnam were characterized by two main actors: small farmers and distributors. Farmers could sell products flexibly at the local market. There was some initial evidence to prove that these chains helped to stabilize the input, output price, and revenue; formulated sustainable income; and increased the satisfaction and confidence of farmers. They eliminated gender discrimination in rural areas and improved livelihood for ethnic minorities. These chains also enhanced the mindset on green, organic, and clean production of farmers, which in turn created environmental benefits. COVID-19 has posed a negative impact on the income of farmers and made them change their production and sales method. Therefore, the research could suggest some policies to sustainably develop the short food supply chains in Vietnam in the future
Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial
Background
Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population.
Methods
AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921.
Findings
Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months.
Interpretation
Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke
Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants
Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks
Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)
From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions
Enhancement of Rhodamine B Degradation by Ag Nanoclusters-Loaded g-C3N4 Nanosheets
In this paper, silver (Ag) nanoclusters-loaded graphitic carbon nitride (g-C3N4) nanosheets are synthesized and their physical properties as well as photocatalytic activities are systematically investigated by different techniques. The existence of Ag atoms in the form of nanoclusters (NCs) rather than well-crystallized nanoparticles are evidenced by X-ray diffraction patterns, SEM images, and XPS spectra. The deposition of Ag nanoclusters on the surface of g-C3N4 nanosheets affect the crystal structure and slightly reduce the band gap energy of g-C3N4. The sharp decrease of photoluminescence intensity indicates that g-C3N4/Ag heterojunctions successfully prevent the recombination of photo-generated electrons and holes. The photocatalytic activities of as-synthesized photocatalysts are demonstrated through the degradation of rhodamine B (RhB) solutions under Xenon lamp irradiation. It is demonstrated that the photocatalytic activity depends strongly on the molar concentration of Ag+ in the starting solution. The g-C3N4/Ag heterojunctions prepared from 0.01 M of Ag+ starting solution exhibit the highest photocatalytic efficiency and allow 100% degradation of RhB after being exposed for 60 min under a Xenon lamp irradiation, which is four times faster than that of pure g-C3N4 nanosheets
The TÍNH KHÁNG KHÁNG SINH CỦA Vibrio spp. PHÂN LẬP TỪ NƯỚC NUÔI THỦY SẢN Ở MỘT SỐ KHU VỰC MIỀN BẮC VIỆT NAM
Antibiotic resistance is a serious global problem, especially in aquaculture. In this study, we evaluated the antibiotic resistance of Vibrio spp. isolated from aquaculture water in shrimp and fish farming areas of five provinces of Northern Vietnam. There were 86 bacterial samples isolated, belonging to four species of Vibrio sp., in which V. parahaemolyticus and V. alginolyticus were the two most widespread species on selective TCBS và ChroMagarTMVibrio media. These bacterial samples were used to evaluate their resistance to 13 antibiotics with the agar plate diffusion method according to CLSI standards. The results show that these samples have a very high rate of resistance to ampicillin (100%), amoxicillin (98.84%), streptomycin (84.88%), and oxytetracycline (69.77%); the lowest resistance rate is to phenicol antibiotics: chloramphenicol (32.56%) and florfenicol (31.4%). The multiple antibiotic resistance (MAR) indices were recorded from 0.15 to 1.0. Two isolates were resistant to all 13 antibiotics. The bacterial isolates from aquaculture water of the five areas have a high resistant rate (100%) from four to eight antibiotics. This result suggests a relationship between antibiotic resistance of the bacterial strains and the current use of antibiotics in aquaculture, and this is one of the important bases for developing strategies and plans on the use and control of antibiotics in aquaculture in the localities.Kháng kháng sinh là một vấn đề nghiêm trọng mang tính chất toàn cầu, đặc biệt là trong nuôi trồng thuỷ sản. Trong nghiên cứu này, chúng tôi đã tiến hành đánh giá tính kháng kháng sinh của Vibrio spp. phân lập từ nước nuôi thủy sản tại vùng nuôi tôm, cá của năm tỉnh miền Bắc Việt Nam. Đã có 86 mẫu vi khuẩn được phân lập bao gồm bốn loài Vibrio sp. trong đó phổ biến là V. parahaemolyticus và V. alginolyticus trên môi trường chọn lọc TCBS và ChroMagarTMVibrio. Các mẫu vi khuẩn này đã được sử dụng để đánh giá tính kháng của chúng đối với 13 loại kháng sinh bằng phương pháp khuếch tán trên đĩa thạch theo tiêu chuẩn CLSI. Kết quả cho thấy các mẫu này có tỉ lệ kháng rất cao với ampicillin (100%), amoxicillin (98,84%), streptomycin (84,88%), oxytetracyline (69,77%) và tỉ lệ kháng thấp nhất với nhóm kháng sinh phenicol bao gồm chloramphenicol (32,56%) và florfenicol (31,4%). Chỉ số đa kháng (MAR) được ghi nhận từ 0,15 đến 1,0; hai mẫu vi khuẩn kháng với tất cả 13 loại kháng sinh. Các vi khuẩn phân lập từ năm khu vực thu mẫu nước nuôi thuỷ sản đều có tỉ lệ kháng 100% từ bốn đến tám loại kháng sinh. Kết quả này cho thấy rằng có mối liên hệ giữa tính kháng kháng sinh ở các chủng vi khuẩn với việc sử dụng kháng sinh trong nuôi thuỷ sản hiện nay và đây là một trong những cơ sở quan trọng để xây dựng các chiến lược và kế hoạch sử dụng và kiểm soát thuốc kháng sinh trong nuôi thủy sản tại các địa phương