7,718 research outputs found

    Chiral Anomaly Effects and the BaBar Measurements of the γγπ0\gamma\gamma^{*}\to \pi^{0} Transition Form Factor

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    The recent BaBar measurements of the γγπ0\gamma\gamma^{*}\to \pi^{0} transition form factor show spectacular deviation from perturbative QCD prediction for large space-like Q2Q^{2} up to 34GeV234\,\rm GeV^{2}. When plotted against Q2Q^{2}, Q2F(Q2)Q^{2}F(Q^{2}) shows steady increase with Q2Q^{2} in contrast with the flat Q2Q^{2} behavior predicted by perturbative QCD, and at 34GeV234\,\rm GeV^{2} is more than 50% larger than the QCD prediction. Stimulated by the BaBar measurements, we revisit our previous paper on the cancellation of anomaly effects in high energy processes Z0π0γZ^{0}\to \pi^{0}\gamma, e+eπ0γe^{+}e^{-}\to \pi^{0}\gamma and apply our results to the γγπ0\gamma^{*}\gamma\to \pi^{0} transition form factor measured in the e+ee+eπ0e^{+}e^{-}\to e^{+}e^{-}\pi^{0} process with one highly virtual photon. We find that, the transition form factor F(Q2)F(Q^{2}) behaves as (m2Q2)×(ln(Q2/m2))2(\frac{m^{2}}{Q^{2}})\times (\ln(Q^{2}/m^{2}))^{2} and produces a striking agreement with the BaBar data for Q2F(Q2)Q^{2}F(Q^{2}) with m=132MeVm=132\,\rm MeV which also reproduces very well the CLEO data at lower Q2Q^{2}.Comment: v4, LaTeX, 8 pages, one figure, minor changes(references), to appear in Int. J. Mod. Phys.

    Optimized FRP Wrapping Schemes for Circular Concrete Columns under Axial Compression

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    This study investigates the behavior and failure modes of fiber-reinforced polymer (FRP) confined concrete wrapped with different FRP schemes, including fully wrapped, partially wrapped, and nonuniformly-wrapped concrete cylinders. By using the same amount of FRP, this study proposes a new wrapping scheme that provides a higher compressive strength and strain for FRP-confined concrete, in comparison with conventional fully wrapping schemes. A total of 33 specimens were cast and tested, with three of these specimens acting as reference specimens and the remaining specimens wrapped with different types of FRP (CFRP and GFRP) by different wrapping schemes. For specimens that belong to the descending branch type, the partially-wrapped specimens had a lower compressive strength but a higher axial strain as compared to the corresponding fully-wrapped specimens. In addition, the nonuniformly-wrapped specimens achieved both a higher compressive strength and axial strain in comparison with the fully-wrapped specimens. Furthermore, the partially-wrapping scheme changes the failure modes of the specimens and the angle of the failure surface. A new equation that can be used to predict the axial strain of concrete cylinders wrapped partially with FRP is proposed

    The Distribution of Dengue Virus Serotype in Quang Nam Province (Vietnam) during the Outbreak in 2018

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    Objectives: Quang Nam province in the Centre of Vietnam has faced an outbreak of dengue hemorrhagic fever (DHF) in 2018. Although DHF is a recurrent disease in this area, no epidemiological and microbiological reports on dengue virus serotypes have been conducted mainly due to lack of facilities for such a kind of advanced surveillance. The aim of this study was to detect different dengue virus serotypes in patients’ blood samples. Design and Methods: Suspected cases living in Quang Nam province (Vietnam) and presenting clinical and hematological signs of dengue hemorrhagic fever were included in the study. The screening was performed, and the results were compared by using two methodologies: RT real-time PCR (RT-rPCR) and the Dengue NS1 rapid test. Results: From December 2018 to February 2019, looking both at RT-rPCR [+] and NS1 [+] methodologies, a total of 488 patients were screened and 336 were positive for dengue virus detection (74 children and 262 adults); 273 of these patients (81.3%) underwent viral serotype identification as follows: 12.82% (35/273) D1 serotype, 17.95% (49/273) D2, 0.37% (1/273) D3, 68.50 (187/283) D4, and 0.37% (1/273) D2+D4 serotypes. The RT-rPCR outcomes showed higher sensitivity during the first three days of infection compared to NS1 (92.3% vs. 89.7%). The NS1 increased sensitivity after the first 3 days whilst the RT-rPCR decreased. Conclusions: Advanced surveillance with dengue virus serotypes identification, if performed routinely, may help to predict and prevent further DHF epidemics based on the exposure of the different serotypes during different periods that lead to the intensification of disease severity as a consequence of antibody-dependent enhancement (ADE)

    Review of potential and actual penetration of solar power in Vietnam

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    With the average solar radiation reaching up to 5 kWh/m2, Vietnam is considered as a country showing an excellent potential for solar power production. Since the year 2000, there have been a lot of studies about the potential of this source in Vietnam. So far, many applications of solar power have been implemented on small, medium, and large scales. In fact, the total capacity of current grid-connected solar power plants has exceeded the planned capacity by 2020 nearly 6 times. However, the studies of solar potential in Vietnam are still incomplete. The policies and mechanisms for developing solar power projects have received attention from the authorities but have not been really satisfactory. The infrastructure is still poor and the power system does not keep up with the development of modern grids. This paper reviewed the potential and actual implementation stage of photovoltaic projects in Vietnam. Moreover, the barriers and challenges of institution, technique, economy, and finance have been considered explicitly for the future development of solar energy in Vietnam

    Characterization of salmonella spp. Isolates from swine: Virulence and antimicrobial resistance

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    Salmonella is one of the most important zoonotic pathogens worldwide. Swine represent typical reservoirs of this bacterium and a frequent source of human infection. Some intrinsic traits make some serovars or strains more virulent than others. Twenty-nine Salmonella spp. isolated from pigs belonging to 16 different serovars were analyzed for gastric acid environment resistance, presence of virulence genes (mgtC, rhuM, pipB, sopB, spvRBC, gipA, sodCI, sopE), antimicrobial resistance and presence of antimicrobial resistance genes (blaTEM, blaPSE-1, aadA1, aadA2, aphA1-lab, strA-strB, tetA, tetB, tetC, tetG, sul1, sul2, sul3). A percentage of 44.83% of strains showed constitutive and inducible gastric acid resistance, whereas 37.93% of strains became resistant only after induction. The genes sopB, pipB and mgtC were the most often detected, with 79.31%, 48.28% and 37.93% of positive strains, respectively. Salmonella virulence plasmid genes were detected in a S. enterica sup. houtenae ser. 40:z4,z23:-strain. Fifteen different virulence profiles were identified: one isolate (ser. Typhimurium) was positive for 6 genes, and 6 isolates (3 ser. Typhimurium, 2 ser. Typhimurium monophasic variant and 1 ser. Choleraesuis) scored positive for 5 genes. None of the isolates resulted resistant to cefotaxime and ciprofloxacin, while all isolates were susceptible to ceftazidime, colistin and gentamycin. Many strains were resistant to sulfonamide (75.86%), tetracycline (51.72%), streptomycin (48.28%) and ampicillin (31.03%). Twenty different resisto-types were identified. Six strains (4 ser. Typhimurium, 1 ser. Derby and 1 ser. Typhimurium monophasic variant) showed the ASSuT profile. Most detected resistance genes sul2 (34.48%), tetA (27.58%) and strA-strB (27.58%). Great variability was observed in analyzed strains. S. ser. Typhimurium was confirmed as one of the most virulent serovars. This study underlines that swine could be a reservoir and source of pathogenic Salmonella strains

    The Vietnamese Version of the Brief Illness Perception Questionnaire and the Beliefs about Medicines Questionnaire:Translation and Cross-cultural Adaptation

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    OBJECTIVE: To translate and cross-culturally adapt the Brief Illness Perception Questionnaire (BIPQ) and the Beliefs about Medicines Questionnaire (BMQ) into Vietnamese. METHODS: We followed the guideline by Beaton et al. (2000 & 2007). Stage I: two translators (informed and uninformed) translated the questionnaires. Stage II: the translations were synthesized. Stage III: back translation was performed by two translators fluent in both Vietnamese and English but naïve to the outcome measurement. Stage IV: seven experts reached consensus on the pre-final Vietnamese version (BIPQ-V and BMQ-V). Stage V: field test of the questionnaires on 16 twelve-year-old students and 31 Vietnamese patients. In addition, we determined the internal consistency and test-retest reliability of the questionnaires in 34 Vietnamese patients with acute coronary syndrome. RESULTS: All experts agreed that there was semantic, idiomatic, experiential, and conceptual equivalence between the original and pre-final Vietnamese versions of the BIPQ and BMQ. Cronbach's alpha coefficients of the internal consistency were acceptable for the BMQ-V Specific-Necessity (0.64), BMQ-V Specific-Concerns (0.62), and BMQ-V General-Harm (0.60), with the exception of BMQ-V General-Overuse (0.27). Intra-class correlation coefficients of the test-retest reliability was acceptable for the subscales of BMQ-V (range: 0.77-0.86), and BIPQ-V items (range: 0.62-0.85) with the exception of BIPQ-V 1 (0.44, 95% CI -014-0.72) and BIPQ-V 4 (0.57, 95% CI 0.22-0.81). CONCLUSIONS: The Vietnamese version of BIPQ and BMQ are reliable tools to assess illness perceptions and beliefs about medicines of patients with acute coronary syndrome. Psychometric properties of these questionnaires should be tested in different patient populations

    BIOLOGICAL AMMONIA REMOVAL BY SUBMERGED AERATED FILTER FROM HANOI GROUND WATER

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    Joint Research on Environmental Science and Technology for the Eart

    Synthesis, Characterization, and Impregnation of Some Ionic Liquids on Polymer Membrane for Separation of Carbon Dioxide from Its Mixture with Methane

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    Some 1-alkyl-3-methylimidazolium-based ionic liquids were synthesized, characterized, and immobilized on membranes to form supported ionic liquid membranes. The supported ionic liquid membranes were characterized by SEM. The initial transmembrane pressures were investigated for each type of impregnated membrane. The CO2/CH4 single gas and mixed gas permeability (CO2 and CH4) have been investigated. The results showed that the CO2/CH4 ideal selectivities and mixed gas selectivities reached 15.45 –23.9 and 13.91 – 22.82, respectively (equivalent to separation yields of 93.3 – 95.98 %). The 1-alkyl-3-methylimidazolium acetate impregnated membrane leads to a slightly lower CO2/CH4 selectivity, however, this ionic liquid is stable, free of halogen and has a low price. The impregnated membranes prepared from polyvinylidene fluoride are more stable than those from polyethersulfone support, and have a higher affinity for CO2 compared to other gas. The obtained high CO2/CH4 selectivities indicate that immobilized membranes can be used for CO2 separation processes. This work is licensed under a Creative Commons Attribution 4.0 International License
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