65 research outputs found

    Liver Involvement Associated with Dengue Infection in Adults in Vietnam

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    Globally, the number of adults hospitalized with dengue has increased markedly in recent years. It has been suggested that hepatic dysfunction is more significant in this group than among children. We describe the spectrum and evolution of disease manifestations among 644 adults with dengue who were prospectively recruited on admission to a major infectious disease hospital in southern Vietnam and compare them with a group of patients with similar illnesses not caused by dengue. Transaminase levels increased in virtually all dengue patients and correlated with other markers of disease severity. However, peak enzyme values usually occurred later than other complications. Clinically severe liver involvement was infrequent and idiosyncratic, but usually resulted in severe bleeding. Chronic co-infection with hepatitis B was associated with modestly but significantly increased levels of alanine aminotransferase, but did not otherwise impact the clinical picture

    Neural Collapse in Deep Linear Networks: From Balanced to Imbalanced Data

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    Modern deep neural networks have achieved impressive performance on tasks from image classification to natural language processing. Surprisingly, these complex systems with massive amounts of parameters exhibit the same structural properties in their last-layer features and classifiers across canonical datasets when training until convergence. In particular, it has been observed that the last-layer features collapse to their class-means, and those class-means are the vertices of a simplex Equiangular Tight Frame (ETF). This phenomenon is known as Neural Collapse (NC\mathcal{NC}). Recent papers have theoretically shown that NC\mathcal{NC} emerges in the global minimizers of training problems with the simplified ``unconstrained feature model''. In this context, we take a step further and prove the NC\mathcal{NC} occurrences in deep linear networks for the popular mean squared error (MSE) and cross entropy (CE) losses, showing that global solutions exhibit NC\mathcal{NC} properties across the linear layers. Furthermore, we extend our study to imbalanced data for MSE loss and present the first geometric analysis of NC\mathcal{NC} under bias-free setting. Our results demonstrate the convergence of the last-layer features and classifiers to a geometry consisting of orthogonal vectors, whose lengths depend on the amount of data in their corresponding classes. Finally, we empirically validate our theoretical analyses on synthetic and practical network architectures with both balanced and imbalanced scenarios.Comment: 93 pages, 20 figures, 4 tables. Hien Dang and Tho Tran contributed equally to this wor

    Organizational Culture Factors Affect Employees’ Organizational Commitment: A Research in Ho Chi Minh City Logistics Enterprises, Vietnam

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    Research aims: The research aims to evaluate several factors of organizational culture affecting the organizational commitment of employees in logistics enterprises in Ho Chi Minh City (Vietnam).Design/Methodology/Approach: The data were collected based on a survey of respondents who were employees working at logistics enterprises in Ho Chi Minh City. The collected data, consisting of 227 survey questionnaires, were described through statistical analysis, checking Cronbach’s Alpha reliability assessment, employing Exploratory Factor Analysis (EFA), and testing the fit of the research model. Research findings: The results showcased that five components had a statistically significant impact on an employee’s organizational commitment, including (from high to low impact in order) consistency in governance policy, communication within the organization, training and development, rewards and recognition, and teamwork.Theoretical contribution/Originality: The study contributes to and supplements the array of organizational culture topics related to the commitment of employees at companies.Practitioner/Policy implication: The research contributes to the logistics companies' understanding of how to improve the organizational culture to maintain the loyalty of employees in the organization.Research limitation/Implication: The research limitation is that only Ho Chi Minh City logistics enterprises were chosen for the survey. However, there are many cities in Vietnam where logistics companies are located. Thus, the other research can be implemented in other regions in Vietnam and other countries for future studies

    PROVISION CAPACITY OF SERVICE DELIVERY FACILITIES FOR CHILDREN WITH HEARING LOSS IN HAI PHONG, VIETNAM

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    Objective: Hearing loss is a commonly occurring disability that affects 466 million people worldwide. This study aimed at determining the actual situations of early intervention delivery facilities for children with hearing loss. Out of this affected population, 7% are children (34 million) who, along with their families, grapple with the serious lifelong problems that accompany the disease. Methods: This descriptive cross-sectional study was conducted with facilities investigated consisting of a school for the deaf, hospitals, an audiology center, and a social agency in Hai Phong province from January 2013 to December 2014. A sample composed of 353 children was also recruited. Results: The examined facilities suffer from shortcomings in provision capacity, which manifest in deficient materials, supplies and equipment, and human resources; the lack of interdisciplinary coordination of activities; inadequate community awareness; and the unaddressed need for early detection and intervention. The conditions of most of the children (98%) were detected by their families, and among those who were clinically diagnosed, the majority (76.8%) received such diagnosis at central hospitals. Hearing impairment among the children were detected, diagnosed, and subjected to intervention at a very late stage (on average, at ages 22.3, 34, and 32.5 months, respectively), thereby compelling up to 63.6% of the families to struggle with their children’s hearing loss. Conclusion: Solutions to current interventions are needed to enhance service delivery systems and guarantee early detection as well as timely and appropriate treatment

    Fed-LSAE: Thwarting Poisoning Attacks against Federated Cyber Threat Detection System via Autoencoder-based Latent Space Inspection

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    The significant rise of security concerns in conventional centralized learning has promoted federated learning (FL) adoption in building intelligent applications without privacy breaches. In cybersecurity, the sensitive data along with the contextual information and high-quality labeling in each enterprise organization play an essential role in constructing high-performance machine learning (ML) models for detecting cyber threats. Nonetheless, the risks coming from poisoning internal adversaries against FL systems have raised discussions about designing robust anti-poisoning frameworks. Whereas defensive mechanisms in the past were based on outlier detection, recent approaches tend to be more concerned with latent space representation. In this paper, we investigate a novel robust aggregation method for FL, namely Fed-LSAE, which takes advantage of latent space representation via the penultimate layer and Autoencoder to exclude malicious clients from the training process. The experimental results on the CIC-ToN-IoT and N-BaIoT datasets confirm the feasibility of our defensive mechanism against cutting-edge poisoning attacks for developing a robust FL-based threat detector in the context of IoT. More specifically, the FL evaluation witnesses an upward trend of approximately 98% across all metrics when integrating with our Fed-LSAE defense

    All-dielectric Metamaterial for Electromagnetically-induced Transparency in Optical Region

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    Metamaterial (MM) is emerging as a promising approach to manipulate electromagnetic waves, spanning from radio frequency to the optical region. In this paper, we employ an effect called electromagnetically-induced transparency (EIT) in all-dielectric MM structures to create a narrow transparent window in opaque broadband of the optical region (580-670 nm). Using dielectric materials instead of metals can mitigate the large non-radiative ohmic loss on the metal surface. The unit-cell of MM consists of Silicon (Si) bars on Silicon dioxide (SiO2_{2}) substrate, in which two bars are directed horizontally and one bar is directed vertically. By changing the relative position and dimension of the Si bars, the EIT effect could be achieved. The optical properties of the proposed MM are investigated numerically using the finite difference method with commercial software Computer Simulation Technology (CST). Then, characteristic parameters of MM exhibiting EIT effect (EIT-MM), including Q-factor, group delay, are calculated to evaluate the applicability of EIT-MM to sensing and light confinement

    The effect of participatory community communication on HIV preventive behaviors among ethnic minority youth in central Vietnam

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    <p>Abstract</p> <p>Background</p> <p>In Vietnam, socially marginalized groups such as ethnic minorities in mountainous areas are often difficult to engage in HIV research and prevention programs. This intervention study aimed to estimate the effect of participatory community communication (PCC) on changing HIV preventive ideation and behavior among ethnic minority youth in a rural district from central Vietnam.</p> <p>Methods</p> <p>In a cross-sectional survey after the PCC intervention, using a structured questionnaire, 800 ethnic minority youth were approached for face-to-face interviews. Propensity score matching (PSM) technique was then utilized to match these participants into two groups-intervention and control-for estimating the effect of the PCC.</p> <p>Results</p> <p>HIV preventive knowledge and ideation tended to increase as the level of recall changed accordingly. The campaign had a significant indirect effect on condom use through its effect on ideation or perceptions. When intervention and control group statistically equivalently reached in terms of individual and social characteristics by PSM, proportions of displaying HIV preventive knowledge, ideation and condom use were significantly higher in intervention group than in matched control counterparts, accounting for net differences of 7.4%, 12.7% and 5%, respectively, and can be translated into the number of 210; 361 and 142 ethnic minority youth in the population.</p> <p>Conclusions</p> <p>The study informs public health implications both theoretically and practically to guide effective HIV control programs for marginalized communities in resources-constrained settings like rural Vietnam and similar contexts of developing countries.</p

    H2_{2}O2_{2} production in Lactobacillus strains isolated from the intestinal microbiome of healthy people

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    Lactobacillus sp. in the digestive tract are capable of producing H2O2 to inhibit the growth of harmful bacteria and balance the gut microflora. In this study, we have isolated 115 strains of Lactobacillus spp. from stool samples of healthy people in Ha Noi. Of the 50 tested Lactobacillus strains, 9 strains were capable of producing H2O2, of which the Lac.VFE-14 strain produced highly H2O2 with a concentration of 2.183 mM, followed by Lac.VFE-08 strains (2.081 mM) and Lac.VFE-04 (2.067 mM). All three strains grew well in MRS medium supplemented with bile salts or adjusted to low pH value. With 0.3% of bile salt, the survival rates of these 3 strains were 99%, 95% and 97%, respectively. At pH 3.0, after 3 hours of cultivation, the survival rates of the three strains were 98.54%, 94.15% and 95.27%, respectively. In addition, each of the cell-free culture supernatants of these three strains that inhibit the growth of S. aureus ATCC-23235. The inhibition zone diameters of the three strains were 19.0±1.0 mm, 14.0±1.0 mm and 11.7±1.3 mm, respectively. The results of 16S rRNA gene analyses showed that Lac.VFE-14, Lac.VFE-08 and Lac.VFE-04 had high similarity scores with L. plantarum ZZU 23 (100%), L. rhamnosus JCM 1136 (99%) and L. plantarum S7 (98.65%), respectively. This study indicates that all three strains have the potential to be used as probiotics in the future. 

    Diagnostic Accuracy of NS1 ELISA and Lateral Flow Rapid Tests for Dengue Sensitivity, Specificity and Relationship to Viraemia and Antibody Responses

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    Dengue is a viral infection of humans that is transmitted by mosquitoes. Dengue is a very important public health problem in many developing countries. Recently, new tests to help diagnose patients with dengue have been developed. Evaluating these tests to see how well they perform in different countries and in different health care settings is an important process that helps to guide health care policy on whether these assays are likely to be useful in making a diagnosis, and if so, when best to use them. Our hospital-based results, using two different types of NS1 tests for diagnosing dengue, indicates that these tests are most sensitive when used during the first 3 days of illness and are most likely to be positive if the patient has primary dengue. Our results also show that a positive NS1 test result is a reflection of the amount of virus in the blood, so that patients with high amounts of virus in the blood are more likely to be NS1 positive. Collectively, the results indicate these NS1 tests deserve inclusion in the diagnostic approach to dengue

    Effectiveness of perindopril/amlodipine fixed-dose combination in the treatment of hypertension: a systematic review

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    Background: Uncontrolled blood pressure is a major risk factor for cardiovascular diseases. Fixed-dose combination (FDC) therapy offers a promising approach to addressing this challenge by providing a convenient single-tablet solution that enhances the effectiveness of blood pressure control. In our systematic review, we assess the effectiveness of perindopril/amlodipine FDC in managing blood pressure.Methods: We conducted a comprehensive search across four primary electronic databases, namely, PubMed, Virtual Health Library (VHL), Global Health Library (GHL), and Google Scholar, as of 8 February 2022. Additionally, we performed a manual search to find relevant articles. The quality of the selected articles was evaluated using the Study Quality Assessment Tools (SQAT) checklist from the National Institute of Health and the ROB2 tool from Cochrane.Results: Our systematic review included 17 eligible articles. The findings show that the use of perindopril/amlodipine FDC significantly lowers blood pressure and enhances the quality of blood pressure control. Compared to the comparison group, the perindopril/amlodipine combination tablet resulted in a higher rate of blood pressure response and normalization. Importantly, perindopril/amlodipine FDC contributes to improved patient adherence with minimal side effects. However, studies conducted to date have not provided assessments of the cost-effectiveness of perindopril/amlodipine FDC.Conclusion: In summary, our analysis confirms the effectiveness of perindopril/amlodipine FDC in lowering blood pressure, with combination therapy outperforming monotherapy and placebo. Although mild adverse reactions were observed in a small subset of participants, cost-effectiveness assessments for this treatment remain lacking in the literature
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