145 research outputs found
Large displacements of FGSW beams in thermal environment using a finite element formulation
The large displacements of functionally graded sandwich (FGSW) beams in thermal environment are studied using a finite element formulation. The beams are composed of three layers, a homogeneous core and two functionally graded face sheets with volume fraction of constituents following a power gradation law. The material properties of the beams are considered to be temperature-dependent. Based on Antman beam model and the total Lagrange formulation, a two-node nonlinear beam element taking the effect of temperature rise into account is formulated and employed in the study. The element with explicit expressions for the internal force vector and tangent stiffness matrix is derived using linear interpolations and reduced integration technique to avoid the shear locking. Newton-Raphson based iterative algorithm is employed in combination with the arc-length control method to compute the large displacement response of a cantilever FGSW beam subjected to end forces. The accuracy of the formulated element is confirmed through a comparison study. The effects of the material inhomogeneity, temperature rise and layer thickness ratio on the large deflection response of the beam are examined and highlighted
CONCEPTS AND AWARENESS ABOUT SELF-HARM AND SUICIDAL THOUGHTS AMONG HIGH SCHOOL STUDENTS CURRENTLY
The article focuses on understanding concepts and awareness of suicidal thoughts and self – harm behaviors based on quantitative and qualitative data. The quantitative database will be taken from a survey of high school students living and studying in Ho Chi Minh City. The qualitative database is taken from in-depth interviews focusing on teachers, parents, and students. The article presents the main results of the research. First, focus on the research basis including subjects, objects, and research methodology. Second, include views on suicidal thoughts and self-harm from many different perspectives, manifestations and causes of these behaviors, the prevalence of self-harm/suicidal thoughts, and consequences. Third, conclude and propose some recommendations to minimize the problem
Assessing local people’s satisfaction on resettlement arrangements of A Luoi Hydropower project, Thua Thien Hue Province
This study aims to estimate the level of satisfaction about resettlement arrangements for local people who have been affected by A Luoi hydroelectric construction project in the Thua Thien Hue province. This research used the Likert scale method to assess the satisfaction level of 98 households living in two of the resettlement sites. Results illustrate that there is variations in the level of satisfaction of local people in the two resettlement sites, Hong Thuong and Hong Ha. In the resettlement area (RA) of the Hong Thuong Commune, people are dissatisfied with the location arrangement. There is a lack of quality in the houses built, been damaged, cracked and degraded, since the construction design is not appropriate for the customs and practices of local people, with a satisfaction rating of 1.07. Meanwhile, at the resettlement site of the Hong Ha commune, people felt satisfied with the arrangement site of the RA and allocated residential land area with the satisfaction rating of 4.19. Our results will help the government, as well as the project owners, to understand the points of dissatisfaction of local people in order to have accordant solutions, ensuring the stable life for local people in those settlement areas.Nghiên cứu này nhằm mục đích đánh giá được mức độ hài lòng của người dân về việc bố trí tái định cư (TĐC) cho người dân bị ảnh hưởng bởi dự án xây dựng thuỷ điện A Lưới, tỉnh Thừa Thiên Huế. Nghiên cứu đã sử dụng phương pháp thang đo Likert để đánh giá mức độ hài lòng của 98 hộ dân sống tại hai khu tái định cư Hồng Thượng và Hồng Hạ. Kết quả nghiên cứu đã cho thấy có sự khác nhau về mức độ hài lòng của người dân tại hai khu TĐC. Tại khu TĐC Hồng Thượng người dân thấy không hài lòng về địa điểm bố trí TĐC, nhà ở được xây dựng thiếu chất lượng đã bị hư hỏng, nứt nẻ xuống cấp, thiết kế xây dựng không phù hợp với phong tục, tập quán của người dân địa phương, với chỉ số đánh giá hài lòng là 1,07. Trong khi đó, tại khu TĐC xã Hồng Hạ người dân lại thấy hài lòng về điểm bố trí TĐC và diện tích đất ở được cấp, với chỉ số đánh giá hài lòng là 4,19. Kết quả nghiên cứu của đề tài sẽ giúp cho chính quyền cũng như chủ đầu tư dự án nắm rõ những điểm không hài lòng của người dân để có hướng giải quyết phù hợp nhằm đảm bảo cuộc sống ổn định cho người dân tại nơi tái định cư
Why adaptation falters:principles for climate change adaptation policy assessment in Vietnam
PurposeRecognition that not every climate adaptation policy is a good one has shifted attention to new tools and methods to measure the adequacy and effectiveness of adaptation policies. This study aims to propose and apply and applies an innovative adaptation policy assessment framework to identify the extent to which climate adaptation policies in Vietnam exhibit conditions that are likely to ensure a sufficient, credible and effective adaptation.Design/methodology/approachIn total, 21 conditions, categorized under five normative principles and covering critical issue areas in adaptation domain, form the climate adaptation policy assessment framework. The principles were double-checked and tested in case studies through observations and analyses of policy documents to ensure that each condition should be distinct and not overlapping across principles. To see if the principles and attendant conditions were able to capture all relevant aspects of adaptation, the authors used structured expert judgment. In total, 39 policy documents pertaining to climate change adaptation were selected for qualitative document analysis. In-depth interviews with local officials and experts were conducted to address data gaps.FindingsThe study reveals major weaknesses constituting a reasonably worrisome picture of the adaptation policies in Vietnam since several critical conditions were underrepresented. These results shed new light on why some adaptation policies falter or are posing adverse impacts. The findings suggest that a sound policy assessment framework can provide evidence on what effective adaptation policy looks like and how it can be enabled. The framework for climate adaptation policy assessment in this study can be easily adjusted and used for different socio-environmental contexts in which new conditions for policy assessment might emerge.Social implicationsThe findings show underlying weaknesses constituting a reasonably worrisome picture of the adaptation regime in Vietnam. In the absence of mechanisms and measures for accountability and transparency in policy processes, adaptation in Vietnam appears more likely to be prone to maladaptation and corruption. While solving these problems will not be easy for Vietnam, the government needs to evaluate whether the short-term gains in sustaining the existing adaptation policies really make progress and serve its long-term climate-adaptive development goals.Originality/valueAlthough interpretations of adaptation effectiveness may be very divergent in different normative views on adaptation outcomes, the authors argue that a common, agreed-upon effectiveness can be reached if it is clearly defined and measurable in adaptation policies. Thus, the climate adaptation policy assessment framework proposed in this study is critical for policymakers, practitioners, donors and stakeholders dealing with adaptation to better understand the weaknesses in policymaking processes, pinpoint priority areas of action and timely prevent or prepare for possible adverse impacts of policies
Observation of High Doppler Velocity Wings in the Nascent Wind of R Doradus
We study the morpho-kinematics in the nascent wind of AGB star R Doradus in the light of high Doppler velocity wings observed in the spectral lines of several species. We probe distances from the star between ∼10 and ∼100 au using ALMA observations of the emission of five different molecular lines. High Doppler velocity enhancements of the line emission are observed in the vicinity of the line of sight crossing the star, reminiscent of those recently interpreted as gas streams in the nascent wind of a similar AGB star, EP Aqr. They are present in both blue-shifted and red- shifted hemispheres but are not exactly back-to-back. They are accelerated at a typical rate of 0.7 km s au up to some 20 km s. Important differences are observed between the emissions of different molecules. We exclude an effect of improper continuum subtraction. However, in contrast to EP Aqr, the line of sight plays no particular role in the R Dor morpho-kinematics, shedding doubt on the validity of a gas stream interpretation. We discuss possible interpretations in terms of stellar pulsations or of rotation of the gas in the environment of the star. We conclude that, in the state of current knowledge, no fully convincing picture of the physics governing the production of such high velocities, typically twice as large as the terminal velocity, can be reliably drawn. New high resolution analyses of observations of the nascent wind of oxygen-rich AGB stars are needed to clarify the issue
Isolation and screening marine fungi with antimicrobial activity from samples collected in Nha Trang bay, VietNam
The marine environment is an extremely complex ecosystem and contains a broad spectrum of fungal diversity. Marine fungi have been shown to be tremendous sources for new and biologically active secondary metabolites. The present study aims to isolate and screen antimicrobial properties of 100 fungus strains from different marine sources including seaweeds, soft corals, sponges and sediment collected at Nha Trang Bay, Vietnam. In preliminary experiments, the crude extracts of these fungal isolates with ethyl acetate were screened for their antimicrobial activity against the human microbial pathogens including Bacillus cereus ATCC 11778, Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Listeria monocytogenes ATCC 19111, Streptococcus faecalis ATCC 19433 and Candida albicans ATCC 10231 by the disc diffusion method. Among the 100 isolates, 59 strains exhibited antimicrobial activity against at least two tested pathogens, that 57% against S. aureus, 50% against L. monocytogenes, 49% against B. cereus, 45% against S. faecalis, 7% against E. coli, 5% against C. albicans, and only 2% against P. aeruginosa. The present study has revealed the presence of high numbers of marine fungi from Nha Trang waters having antimicrobial properties and they need to be investigated further for natural bioactive products
Effect of cultural conditions on antimicrobial activity of marine-derived fungus Penicillium chrysogenum
Marine fungi are a potential source of structurally diversified bioactive secondary metabolites that are not found in terrestrial sources. In our continuous investigation to search new antimicrobial agents from marine-derived fungi, we isolated fungal strain 045-357-2 from a soft coral sample collected from Ca Na bay, Ninh Thuan, Vietnam. The strain showed high antibacterial activity and was selected for further study. According to Internal Transcribed Spacer (ITS) rDNA molecular methods, the fungus was identified as Penicillium chrysogenum 045-357-2 and had a 100% homology (600/600 bp) with a GenBank sequence from a reference P. chrysogenum strain (NCBI accession no. EF200090). In the present investigation, the fungus was studied on effect of different culture incubation period, pH and salinity for antimicrobial activity against pathogenic microbes including Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Streptococcus faecalis, Listeria monocytogenes, and Candida albicans. The ethyl acetate extracts of culture medium of the fungal isolate were determined antimicrobial activity by disc diffusion assay. The results showed that the optimum antimicrobial activity of the fungal strain P. chrysogenum 045-357-2 was obtained in medium containing 20 g rice, 20 mg yeast extract, 10 mg KH2PO4 , and 40 mL natural seawater at 30oC on the 14th day of incubation. The strain also exhibited highest antimicrobial activity in the medium at initial pH 6.0 – 8.0 and salinity of 35 g/L. The findings indicate that cultural conditions significantly influenced on antimicrobial activity of the studied fungus. The optimization is potential use for further study on the mass cultivation and isolation of bioactive compounds for this fungus
Spondylolysis-induced Multilevel Lumbar Spondylolisthesis; Challenges in Lumbar Spine Surgery
Lumbar spondylolysis and multilevel lumbar spondylolysis account for 4.4-5.8% and 0.3% of the general population, and multilevel lumbar spondylolysis resulting in spondylolisthesis is even rarer. Herein, we report two cases of three-level lumbar spondylolisthesis because of spondylolysis: A 49-year-old woman was admitted to the hospital for dull lower back pain over the past 8 months, with exacerbating symptoms when standing and walking. Spasticity at lumbar region and radiculopathy at S1 nerve root was found on examination and a 63-year-old man was admitted to the hospital because of numbness and perianal sensory disturbances with difficulty urinating 2 weeks ago, the symptoms gradually increased to the time of examination. Both patients were diagnosed with multilevel lumbar spondylolisthesis because of spondylolysis and were indicated for posterior lumbar interbody fusion (PLIF). After surgery, both patients recovered well without any significant complications. The improved treatment results suggest the application of PLIF technique to treat spondylolysis-induced multilevel lumbar spondylolisthesis
HAEMAGGLUTINATION ACTIVITY OF THE EXTRACTS FROM SOME VIETNAM MARINE INVERTEBRATES
Aqueous extracts from 21 species of Vietnam marine invertebrates, including 11 bivalve and 10 gastropod species, were examined for haemagglutination activity using native and enzyme-treated different animal and human erythrocytes. The 8 bivalve and 10 gastropod species were found to have haemagglutinination activities toward at least one type of erythrocyte tested. A total of 86% of marine invertebrate species surveyed were active. Strong activity was detected in extracts from two bivalve species (Tridacna squamosa and Geloina coaxans) and three gastropod species (Tutufa rubeta, Pleuroploca trapezium and Tectus conus) with enzyme-treated rabbit, horse and human A, B, O erythrocytes. In a haemagglutination–inhibition test with various monosaccharides and glycoproteins, haemagglutination activities of two extracts from T. rubeta and P. trapezium had no affinity for any of the monosaccharides and glycoproteins tested, while activities of the extracts from T. squamosa and T. conus were strongly inhibited by porcine stomach mucin tested, suggesting the presence of lectins specific for O-glycans of these species. The activities of four marine invertebrate extracts were stable over a wide range ofpH and temperature. The haemagglutination activities of T. rubeta and P. trapezium extracts were independent of the presence of divalent cations, whereas the haemagglutination activity of extracts from T. squamosa and T. conus were slightly dependent on the presence of divalent cations. The results suggest that Vietnam marine invertebrates may be good sources of useful lectins for biochemical and biomedical applications
Multivalvular involvement associated with Libman-Sacks endocarditis detected by multimodality imaging: A case report
Libman-Sacks endocarditis accounts for 6–11 percent of systemic lupus erythematosus patients and is associated with varying degrees of valvular dysfunction, increased risk for stroke and transient ischemic attacks, and increased mortality. In previous studies, left-sided valvular Libman-Sacks vegetations were more frequently detected than right sided vegetations; reported cases of bilateral involvement is very rare. A comprehensive clinical assessment and the multimodality imaging is of utmost importance in the management of systemic lupus erythematosus. In this case report, we describe a 31-year-old female patient with uncontrolled systemic lupus erythematosus initially presented with gastrointestinal symptoms but eventually had a vegetation-like structure on the posterior leaflet of the mitral valve which was revealed during routine echocardiography. Two-dimensional/three-dimensional transthoracic and transesophageal echocardiography, cardiac magnetic resonance, and cardiac computed tomography further characterized the mitral valve vegetation and revealed an additional vegetation of the pulmonary valve. Echocardiography remains the cornerstone for the detection of Libman-Sacks vegetations. Cardiac MRI and cardiac CT are useful in characterizing lesion size and effects and may prove particularly helpful in the assessment of right-sided or multivalvular endocarditis. The presence of focal brain lesions on brain MRI prompted antithrombotic therapy
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