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The research aims to determine the conditions that affect the tourism development of a destination through the evaluation of tourists (in the case of Sapa town, Lao Cai province, Vietnam). Using quantitative methods, the article uses SPSS software to process interview results from 400 tourists according to four groups of factors: (i) accessibility to public communication services, hotel amenities and hygiene, level of convenience and comfort of sightseeing transportation; (ii) the adequacy, capacity, and hygiene of the parking lot, the diversity and specificity of souvenirs, the attractiveness and diversity of entertainment activities, (iii) security issues, order, and safety and (iv) the quality of tourism human resources. The research results show a group of conditions, such as the adequacy, capacity, and hygiene of the parking lot, the diversity and specificity of souvenirs, and the attractiveness and diversity of entertainment activities. Location and natural landscape have the strongest impact on the development of a tourist destination. While factors in groups I, iii, and iV have a lower level of influence. From there, this study proposes policy implications for improving the service quality of the destination, such as: the issue of human resource training, the quality of infrastructure; renewing products and services, and diversifying local cultural experiences. In particular, the quality of human resources is an issue that needs improvement not only in Sapa but also for many tourist destinations in mountainous regions of Vietnam [ABSTRACT FROM AUTHOR]

Density functional theory and a semi-empirical quantum chemical approach were used to evaluate the photocatalytic efficiency of ceria (CeO2) combined with reduced graphene oxide (rGO) and graphene (GP) for degrading methylene blue (MB). Two main aspects were examined: the adsorption ability of rGO and GP for MB, and the separation of photogenerated electrons and holes in CeO2/rGO and CeO2/GP. Our results, based on calculations of the adsorption energy, population analysis, bond strength index, and reduced density gradient, show favorable energetics for MB adsorption on both rGO and GP surfaces. The process is driven by weak, non-covalent interactions, with rGO showing better MB adsorption. A detailed analysis involving parameters like fractional occupation density, the centroid distance between molecular orbitals, and the Lewis acid index of the catalysts highlights the effective charge separation in CeO2/rGO compared to CeO2/GP. These findings are crucial for understanding photocatalytic degradation mechanisms of organic dyes and developing efficient photocatalysts. [ABSTRACT FROM AUTHOR]

In this study, we use a time-varying parameter vector autoregression in conjunction with the extended joint connectedness approach (TVPVAR-EJC) to examine the interrelationships among five variables, namely digitalization measured by the number of individuals using the Internet (% of the population), mobile cellular subscriptions (per 100 people), human capital index, CO2 emissions, and GDP, from 1996 to 2019 in Vietnam. Net total directional connectedness of digitalization and other variables suggests that it consistently acts as a net shock transmitter, whereas human capital was found to be a net receiver of corresponding shocks from 1997 to 2019. The emission of CO2 was a net critical receiver in 1998 but remained as a net transmitter for the rest of the period. Pairwise connectedness reveals that digitalization appeared as a net shock transmitter in connection with the human capital index and GDP. In the relationship with human capital, digitalization's role was critical. [ABSTRACT FROM AUTHOR]

Complex shear modulus imaging (CSMI) is a technique used to determine the elasticity and viscosity of soft tissues; it aids in investigating tissue structure and detecting tumors. CSMI methods can be categorized into quasi-static and dynamic approaches. The dynamic method utilizes force excitation and particle velocity measurements to estimate the Complex Shear Modulus (CSM). However, noise poses a challenge to shear wave estimation, affecting accuracy. Researchers are actively exploring adaptive filtering techniques and signal processing algorithms to address the noise issue and obtain reliable shear wave estimations. By integrating the Algebraic Helmholtz Inversion (AHI) method and the Least Mean Square (LMS) filter, imaging accuracy can be enhanced by mitigating the impact of noise. This study introduces a pioneering advancement in Complex Shear Modulus Imaging (CSMI). A new approach is proposed, using a dual-frequency excitation technique, strategically employing 100 Hz and 150 Hz frequencies. The proposed method is meticulously designed to enhance the overall efficiency of CSMI. Furthermore, a highly effective signal sampling and spectrum estimation procedure is introduced, aimed at elevating the accuracy of Algebraic Helmholtz Inversion (AHI) and significantly mitigating computational complexity in contrast to prior investigations. [ABSTRACT FROM AUTHOR]

Evaluation of the arsenic content in food has always been an important issue due to its high toxicity. This is especially relevant for Vietnam, a country with high arsenic contamination. The present study focuses on the development of a model function to predict As uptake in the vegetable Brassica perviridis as a function of the conditions of plant growth and soil parameters. The content of the As and Fe in the samples was determined by neutron activation analysis at the IBR-2 reactor; the soil pH and total organic carbon content were measured in the Institute of Nuclear Science and Technology –Vietnam Atomic Energy Institute (Hanoi, Vietnam). Obtained data have shown that As uptake in the Brassica perviridis plants grown in northern Vietnam could be presented as a function of soil parameters such as pH, organic carbon content, and Fe content, but is not dependent on As content in soil. Particularly high Fe content in Vietnamese soils contribute to As immobilization and prevent its uptake by plants. Regression Data Analysis was used to extract the model function with good corresponding statistics: correlation factor R > 0.97, the probability p-value of independent variable coefficients in the range from 1.86E-07 to 0.007, and the significance F of the model < 1.49E-11. The obtained values demonstrate the reliability and the trueness of the applied model at given soil characteristics and conditions of plants cultivation. The concertation of As in irrigating water could be regarded as the main source of the As uptake in plants and need to be investigated. [ABSTRACT FROM AUTHOR]

The tight-binding quantum chemical method (GFN2-xTB) was performed to study the nature of the interaction between the two components in a cellulose–chitosan composite (CCS) and its adsorption ability for Ni2+ and NiOH+. The interaction energy, topology of bond paths, frontier molecular orbitals, Fukui functions, and molecular electrostatic potentials were calculated and analysed to figure out the interaction between the components in the CCS. The obtained results show that cellulose and chitosan mainly interact via the formation of hydrogen bonds and van der Waals forces. The CCS shows high adsorption ability for Ni2+ and NiOH+. The preferred adsorption sites of Ni(II) on the CCS were determined and analysed. The improvement in adsorption ability of CCS over pristine cellulose and chitosan was attributed to the changes in structure and electronic properties of the material due to the interaction between the components. [ABSTRACT FROM AUTHOR]

The chemical investigation of Homotrigona apicalis propolis collected in Binh Dinh province, Vietnam, led to the isolation of nine compounds, including four sesquiterpenes: spathulenol (1), 1αH,5βH-aromandendrane-4β,10α-diol (2), 1β,6α-dihydroxy-4(15)-eudesmene (3), and 1βH,5βH-aromandendrane-4α,10β-diol (4); three triterpenes: acetyl oleanolic acid (5), 3α-hydroxytirucalla-8,24-dien-21-oic acid (6), and ursolic acid (7); and two xanthones: cochinchinone A (8) and α-mangostin (9). Sesquiterpens 1–4 and triterpene 6 were isolated for the first time from stingless bee propolis. Plants in the Cratoxylum and Aglaia genus were suggested as resin sources of the propolis sample. In the antibacterial activity evaluation, the EtOH extract only showed moderate activity on S. aureus, while the isolated compounds 7–9 showed good antibacterial activity, with IC50 values of 0.56 to 17.33 µg/mL. The EtOH extract displayed selective cytotoxicity against the A-549 cancer cell line, with IC50 values of 22.82 ± 0.86 µg/mL, and the xanthones 8 and 9 exhibited good activity against the KB, HepG-2, and A-549 cancer cell lines, with IC50 values ranging from 7.55 ± 0.25 µg/mL to 29.27 ± 2.07 µg/mL. The cytotoxic effects of xanthones 8 and 9 were determined by the inhibition of the EGFR and HER2 pathways using a molecular docking study. Compounds 8 and 9 displayed strong binding affinity with EFGR and HER2, with values of −9.3 to −9.9 kcal/mol. Compounds 5, 8, and 9 showed potential α-glucosidase inhibitory activities, which were further confirmed by computational studies. The binding energies of compounds 5, 8, and 9 were lower than that of arcabose. [ABSTRACT FROM AUTHOR]

Three new xanthones, garcimckeans A-C (1-3) were isolated from the methanol extract of the stems of Garcinia mckeaniana (Clusiaceae). Their structures were established by extensive spectroscopic analysis (HR-ESI-MS and 1 D and 2 D NMR) and by comparison of the spectral data with those reported in the literature. Compounds 1-3 displayed weak cytotoxic activity toward KB, Lu, HepG2, and MCF7 cell lines using the MTT assay with IC50 values ranging from 71.03 ± 2.93 to 90.40 ± 7.13 µM compared to that of the positive control compound, ellipticine (IC50: 1.22 ± 0.10 ∼ 2.44 ± 0.2 µM). [ABSTRACT FROM AUTHOR]

Background: No specific antiviral drug can effectively treat BKV reactivation after kidney transplantation. Thus, we evaluated stepwise-reduced immunosuppression to treat BKV reactivation. Methods: 341 kidney-transplant recipients were monitored for BKV infection (BKV-viremia, BKV-viruria). Positive samples with a significant virus load were nested PCR-genotyped in the VP1 region. In 97/211 patients presenting BKV viremia ≥104 copies/mL and/or BKV viruria ≥107 copies/mL, or BKV-nephropathy immunosuppression (i.e., mycophenolate mofetil [MMF]) was reduced by 50%. If viral load did not decrease within 28 days, MMF dose was further reduced by 25%, although calcineurin-inhibitor (CNI) therapy remained unchanged. If BKV viral load did not decrease within another 28 days, MMF was withdrawn and replaced by everolimus combined with reduced CNIs. Results: Only 41/97 BKV (+) cases completed the 6-month follow-up. Among these, 29 (71%) were in the BKV-I group and 12 (29%) were in BKV-IV. BKV viruria and BKV viremia were significantly decreased from 9.32 to 6.09 log10 copies/mL, and from 3.59 to 2.45 log10 copies/mL (p < 0.001 and p = 0.024, respectively). 11/32 (34.4%) patients were cleared of BKV viremia; 2/32 (6.3%) patients were cleared of BKV in both serum and urine, and 9/9 (100%) only had BKV viruria but did not develop BKV viremia. eGFR remained stable. No patient with BKV-related nephropathy had graft loss. There was a significant inverse relationship between changes in eGFR and serum BKV load (r = −0.314, p = 0.04). Conclusions: This stepwise immunosuppressive strategy proved effective at reducing BKV viral load in kidney transplant recipients that had high BKV loads in serum and/or urine. Renal function remained stable without rejection. [ABSTRACT FROM AUTHOR]

High concentrations of suspended solids can cause water quality deterioration, leading to ecological degradation of the aquatic environment. In highly eutrophic waters, they are important carriers of pollutants and nutrients. Therefore, quantifying total suspended solids concentration ( C T S S ) is critical for any water quality monitoring program. This study proposes two band ratio algorithms for estimating C T S S in highly eutrophic lakes based on a data set of 180 in situ samples of remote-sensing reflectance, R r s λ , and C T S S measured simultaneously across 10 dates in four lakes and reservoirs in Hanoi (Vietnam). The in situ C T S S ranges from 2.7 to 73.3 mg l−1, averaging at 24.9 mg l−1, and is highly correlated to water transparency (the correlation coefficient, r = 0.73), chl-a concentration ( r = 0.78), and the trophic state index ( r = 0.89). Our analyses demonstrate the appropriateness of the near-infrared/red spectral ratio, R r s 815 / R r s 655 , model (N = 124) for estimating C T S S in the study lakes (the determination coefficient, R 2 = 0.84). The model was then verified with a small error (the root mean square error, RMSE = 4.1 mg l−1) using independent multi-date-obtained data sets (N = 56). The model is further optimized to establish a regional C T S S estimation model for Landsat 8/OLI and Sentinel 2/MSI bands using the 865 and 655 (or 665) nm bands. The band ratios showed reasonable estimations when applying to the respective spectral band ratios, i.e. the OLI's band 5/band 4 ( R 2 = 0.58; RMSE = 7.7) and the MSI band 8/band 4 ( R 2 = 0.73; RMSE = 6.1). [ABSTRACT FROM AUTHOR]

Adsorption of dichlorodiphenyltrichloroethane (DDT) on titanium dioxide supported on graphitic carbon nitride (TiO2/cGN) was investigated using a novel, accurate and broadly parametrized self-consistent tight-binding quantum chemical (GFN2-xTB) method. The adsorption energy, charges on atoms, bond orders and reaction pathway have been determined and analyzed to figure out the nature of the adsorption process. The obtained results indicate that the adsorption of DDT on the pristine cGN is physical of nature. The combination of TiO2 and cGN significantly enhanced the material's adsorption performance. DDT is chemically adsorbed on TiO2/cGN due to the formation of chemical bonds between atoms of DDT and TiO2/cGN. In addition, the adsorption process does not involve a transition state. [ABSTRACT FROM AUTHOR]

A series of substituted 4H-pyrano[2,3-d]pyrimidines were synthesized from corresponding substituted 4H-pyrans by ring-closing reaction with acetic anhydride or acetic acid in the presence of trifluoroacetic acid as catalyst. The successive alkylation reaction of lactam N–H bond on pyrimidine-4-one ring was carried out using propargylic bromide in dry acetonitrile in the presence of anhydrous potassium carbonate. Three procedures applied for this purpose, including MW-assisted heating conditions at power of 100 W, under conventional heating conditions in water bath at 50 °C, and under ultrasound-assisted heating conditions at 50 °C. Dry acetonitrile was used as reaction solvent. Excellent yields of N-propargyl-4H-pyrano[2,3-d]pyrimidine derivatives were obtained. The single-crystal X-ray structure of compound 6a has been recorded, and the study helps to confirm the structure of synthesized N-propargyl derivative of 4H-pyrano[2,3-d]pyrimidines 6a–6p. [ABSTRACT FROM AUTHOR]

Objectives: The purpose of this study was to identify the SNP sites and determine the BKV genotype circulating in kidney-transplant Vietnamese recipients based on the VP1 gene region. Methods: 344 samples were collected from post-kidney-transplant recipients at the 103 Vietnam Military Hospital to investigate the number of BKV infections. Positive samples with a sufficient virus concentration were analyzed by nested PCR in the VP1 region, sequencing detected genotyping and single-nucleotide polymorphism. Results: BKV infection was determined in 214 patients (62.2%), of whom 11 (5.1%) were diagnosed with BKV-associated nephropathy. Among the 90 BKV-I strains sequenced, 89 (98.88%) were strains of I/b-1 and 1 (1.12%) was strain I/b-2. The 60 BKV-IV strains had a greater diversity of subgroups, including 40% IV/a-1, 1.66% IV/a-2, 56.68% IV/c-1, and 1.16% IV/c-2. Additionally, of 11 cases diagnosed with BKVN, seven belonged to subgroup I/b-1 (63.6%) and four to subgroup IV/c-1 (36.4%). Moreover, 22 specific SNPs that were genotype I or IV were determined in this Vietnamese population. Specifically, at position 1745, for the Vietnamese BKV-IV strains, the SNP position (A→G) appeared in 57/60 samples (95%). This causes transformation of the amino acid N→S. This SNP site can enable detection of genotype IV in Vietnam. It represents a unique evolution pattern and mutation that has not been found in other international strains. Conclusion: The BKV-I genotype was more common than BKV-IV; however, mutations that occur on the VP1 typing region of BKV-IV strains were more frequent than in BKV-I strains. [ABSTRACT FROM AUTHOR]

We did not record any complications intra-operation and post-operation, including: co-twin demise, bleeding in the amniotic cavity, PPROM within 24 hours, maternal infection, anesthetic complications, or maternal blood loss requiring transfusion. Firstly, because of the difference in gestational age of the surgical procedure, we performed surgery in the second trimester differently from some studies performed in the third trimester, increasing the risk of premature birth following the procedure. Keywords: laser ablation; selective fetal reduction; twin-twin transfusion syndrome; new fetal medicine center EN laser ablation selective fetal reduction twin-twin transfusion syndrome new fetal medicine center 555 563 9 05/11/22 20220401 NES 220401 Introduction Monochorionic diamniotic (MCDA) twins are high-risk pregnancies with many complications, the most frequent of which is twin-twin transfusion syndrome (TTTS), affecting approximately 15% of MCDA twins.[1],[2] TTTS is associated with up to 90% neonatal mortality and neurological complications in 20% of surviving co-twin if left untreated.1-3 With the purpose of improved outcomes, various treatment modalities have been developed, including amnioreduction, septostomy, selective fetal reduction, and fetoscopic laser surgery (FLS).[2],4-6 Among them, FLS coagulates the placental vascular anastomoses, prevents blood transfusion between the two fetuses, and saves both twins' lives. The surgery was performed in a separate operation room for fetal surgery. [Extracted from the article]

The Northeastern coastal zone of Vietnam possesses high biodiversity and rich ecosystems like coral reefs, seagrasses, beaches and mangroves. It also includes the Ha Long Bay Natural Heritage site (UNESCO 1994) and the Cat Ba Biosphere Reserve (MAB/UNESCO 2004) as well as hosts the Economic Development Triangle (Hai Phong−Ha Noi–Quang Ninh) established by the Government of Vietnam. As one of the coastal ecosystems, sandy beach ecosystems attracted more attention during recent decades because of their essential role for human welfare and in environmental protection. A few studies concentrated on sustainable management of sandy beach based on environmental and ecological protection and enhance the beach quality for recreational use. The DPSIR (Driving force Pressure State Impact Response) framework describes the logical interaction among systems and finds out the cause and consequence of social-economic development activities to the environment and resources. In this study, the DPSIR was applied on the sandy beaches in the Northeastern coast of Vietnam to reveal the main environmental problems on sandy beaches including the decline of the natural landscape around the beaches and the degradation of the environment. It also pointed out that tourism development in association with urbanization and sea reclamation is the main driving forces for environmental degradation of the sandy beaches. Therefore, local authorities of Hai Phong and Quang Ninh should take into account several main responses to policies on inter-province coordination and managerial measures with a wider scope, which integrate socio-economic and physical factors, proximity, accessibility, and neighborhood to manage healthy coastal ecosystems and sandy beaches in particular. An integrated coastal management program for the Northeastern coast of Vietnam needs to be developed and carried out to follow the laws of Vietnam as well as to meet local urgent requirements. [ABSTRACT FROM AUTHOR]

Searching for bioactive agents from medicinal plants, eleven constituents were isolated from Polyscias guilfoylei stem for the first time, including a nucleoside uracil (1), two sterols β-sitosterol (2) and daucosterol (3), a saponin androseptoside A (4), two lignans (+)-pinoresinol (5) and (+)-syringaresinol (6), four phenolic acids protocatechuic acid (7), methyl protocatechuate (8), caffeic acid (9), and 5-O-caffeoylquinic acid (10), and a flavonoid quercitrin (11). Metabolites 1, 4, and 6–11 have never been observed in genus Polyscias before. Phenolic compounds 7 and 9 possessed the respective IC50 values of 21.33 and 13.88 µg/mL in DPPH (2,2-diphenyl-1-picrylhydrazyl) antioxidative assay, as compared with that of the positive control resveratrol (IC50 = 13.21 µg/mL). From density functional theory (DFT) calculated approach, the DPPH free radical scavenging capacity of two compounds 7 and 9 can be explained by the role of OH groups at carbons C-3 and C-4. Antioxidative actions of these two potential agents are followed HAT (H atom transfer) mechanism by OH bond disruption in gas, but SPLET (sequential proton loss electron transfer) mechanism in solvents water and methanol. Compared to 4-OH group, 3-OH group showed better bond disruption enthalpies and better kinetic energies since it reacted with HOO• and DPPH radicals. Sterols 2–3 and flavonoid 11 induced the IC50 values of < 2.0 µg/mL better than the positive control acarbose (IC50 = 184.0 µg/mL) in α-glucosidase inhibitory assay. Their interactions with human intestinal C- and N-terminal domains of α-glucosidase were explored using molecular docking study. The obtained results proved that compounds 2, 3, and 11 bind relatively stronger with the C-terminal domain than to the N-terminal domain through pivotal residues in the binding site and could be hypothesized as mixed inhibitors. [ABSTRACT FROM AUTHOR]

Phytochemical investigation of the ethyl acetate extract of Styrax annamensis leaves has led to the isolation and determination of a new lignan, 7R,8S,7′S,8′R-3,4,3′-trimethoxy-9,4′,7′-trihydroxy-8.8′,7.O.9′-lignan (1), together with a known compound, 4-ketopinoresinol (2). Compound 2 was isolated from the genus Styrax for the first time, and showed moderate activity to capture the DPPH radical with the IC50 value of 56.74 ± 0.79 μg/mL. [ABSTRACT FROM AUTHOR]

Currently, Management Accounting has been interested many researchers, economists as well as Vietnamese enterprises. Management accounting provides useful information about such contents as cost classification and control, cost - volume - profit analysis, estimation, responsibility center analysis, information analysis, believe in making short and long term decisions, thereby helping internal managers make appropriate business decisions. Understand the importance of Management Accounting, the article presents some modern management tools used in management accounting such as: Cost-by-Activity (ABC) Determination, Balanced Scorecard (BSC), Cost accounting and cost management in a lean environment. Vietnam is on the way of applying International Financial Reporting Standards (IFRS) and the above issues of management accounting need to be considered. Through the view of manager awareness and external auditors. We use quantitative research methods based on synthesis analysis of available information from many various sources, interviews through questionnaires for 500 managers and auditors who are currently working in Vietnam in 2019. We figure out some factors influencing IFRS applying including but not limited to business features, accounting team ability, accounting framework, etc. Applying IFRS will need to go in parallel with enhancing management accounting practices in developing nations including Vietnam. There is not so much gap in perception of IFRS applicability among managers in enterprises and auditors, among different groups of people in working experience. Last but not least, this paper contributes to an overview of factors affecting the ability to apply the international accounting standards system in a developing country like Vietnam. At the same time demonstrate that this applicability is influenced by many different factors. [ABSTRACT FROM AUTHOR]

Purpose: In this study, we focused on the role of elevated serum interleukin 6 (IL-6) concentration in predicting 5-year cardiovascular mortality in hemodialysis patients using low-flux dialyzer reuse. Materials and methods: We measured serum IL-6 concentrations in 236 hemodialysis patients (138 males and 98 females) to predict 5-year cardiovascular mortality. We assessed the baseline demographics of all patients who had a mean age of 44 years and a median hemodialysis duration of 38.5 months. We divided all patients into two equal groups based on the serum IL-6 concentration: G1 (n = 118) with serum IL-6 concentration < 6.78 pg/L and G2 (n = 118) with serum IL-6 concentration ≥ 6.78 pg/L. Results: After the 5-year follow-up, 45 patients died due to cardiovascular causes (19.1%). Lipid disorder, hemoglobin, serum albumin, β2-M, and IL-6 concentration were independent risk factors for predicting cardiovascular mortality during the 60-month follow-up in hemodialysis patients. Based on the Kaplan–Meier analysis, we realized that patients with a higher interleukin 6 concentration (G2) had a significantly higher cardiovascular mortality rate than patients in G1 (log-rank test p < 0.001). Serum IL-6 concentration was a better predictor of 5-year cardiovascular mortality than high-sensitivity C-reactive protein in hemodialysis patients using low-flux dialyzer reuse (AUC = 0.818; p < 0.001; cut-off value: 8.055 pg/mL, Se = 77.8%, Sp = 78.5%). Conclusion: Serum IL-6 concentration was a better predictor of 5-year cardiovascular mortality than high-sensitivity C-reactive protein in maintenance hemodialysis patients using low-flux dialysis reuse. [ABSTRACT FROM AUTHOR]

The methanation of carbon over nickel catalysts supported on activated carbon was investigated using a continuous flow microreactor. Catalysts with nickel loadings of 5, 7, and 10 % were synthesised by incipient wetness impregnation methods and characterised using Brunauer–Emmett–Teller (BET), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), H2-temperature-programmed reduction (TPR), BET, XRD, SEM, TEM and H2-TPR. The methanation reaction was studied over the temperature range 200–500°C with a H2 to CO2 ratio of 4 : 1 in He and at 1 atm. With an increase in Ni content from 5 to 7 % both conversion of CO2 and CH4 selectivity increased. Increasing the nickel content to 10 %, however decreased conversion and selectivity due to the larger crystallite size and lower surface area of the catalyst. The most active catalyst with 7 % Ni does not deactivate during 15 h time on stream at 350°C. The high catalytic activity and stability of the studied catalysts is a consequence of the reducibility of Ni and a synergetic effect between the nickel active sites and the activated carbon surface. Catalysts containing nickel on activated carbon are tested for the methanation of CO2. Nickel loads of 5 to 7 wt-% increase both CO2 conversion and CH4 selectivity while >10 wt-% results in larger crystallite size and lower catalyst surface area. The high reducibility of the Ni species leads to the good performance. [ABSTRACT FROM AUTHOR]

The aim of this paper is to introduce a general setting where some well-known results on essentially injective modules, automorphism-(co)invariant modules and small projective modules can be obtained by developing a general theory of modules which are (co)invariant under automorphisms of their covers and envelopes. [ABSTRACT FROM AUTHOR]

Econometric is commonly used in economic forecasting model for short term, long term and it is applied in many different fields. While, neural network models have the advantage for fast calculating and high accuracy due to weight adjustment after training steps. The combination of econometric and neural network models will increase the effective individual models. It can achieve advantages of both econometric and neural network. In this paper, we present a method that combined two models for coffee price forecasting. Experimental results are predicted daily with the number of 427 training samples from the last 1 years with actual data with a mean deviation of 0.00243 indicating that our predictive model has acceptable accuracy. [ABSTRACT FROM AUTHOR]

The task of researching and developing information retrieval systems is becoming important in the big data age. Current search methods try to mention to fast searching based on keyword matching or similar semantic between query and documents but have not got a really effective engine for semantic search . In this paper, we propose a method for information retrieval based on probability inference with the DLMC model to search by semantic equivalents and a topic word with score for fast searching. Results of the experimental with 952 Vietnamese documents show that our method is really effective for Vietnamese document retrieval system. [ABSTRACT FROM AUTHOR]

We investigate the global exponential stability of equilibrium solutions of a projected dynamical system for variational inequalities. Under strong pseudomonotonicity and Lipschitz continuity assumptions, we prove that the dynamical system has a unique equilibrium solution. Moreover, this solution is globally exponentially stable. Some examples are given to analyze the effectiveness of the theoretical results. The numerical results confirm that the trajectory of the dynamical system globally exponentially converges to the unique solution of the considered variational inequality. The results established in this paper improve and extend some recent works. [ABSTRACT FROM AUTHOR]

Monitoring chlorophyll-a concentration (Chl-a) in inland waters, particularly hypertrophic lake waters in megacities, is a critically important environmental issue. To enable long-term Chl-a monitoring using Landsat series sensors, development of a Chl-a estimation algorithm for the new Landsat sensor is requisite. This study aims to identify the most accurate algorithm for Chl-a estimation in hypertrophic waters using Landsat 8 images and in situ Chl-a data from West Lake and nine other hypertrophic lakes in Hanoi (Vietnam's capital). The best estimation was obtained by the ratio of two reflectances at 562 and 483 nm, corresponding to the ratio of the OLI band 3 versus band 2, termed the GrB2 algorithm. The GrB2 values using the reflectances of water samples and the Landsat images were correlated with the Chl-a by an exponential function (r2 = 0.64 to 0.82), and the estimated Chl-a were verified by the smallness of standard error (smaller than 10%) and degree of conformity with recent fish-kill phenomena that commonly occur in those lakes in summer and early spring. Because the availability of GrB2 is limited to waters with low levels of inorganic suspended matter, its extension to waters with much higher levels requires further investigation. [ABSTRACT FROM PUBLISHER]

The prevalence of global arsenic groundwater contamination has driven widespread research on developing effective treatment systems including adsorption using various sorbents. The uptake of arsenic-based contaminants onto established sorbents such as activated carbon (AC) can be effectively enhanced via immobilization/impregnation of iron-based elements on the porous AC surface. Recent suggestions that AC pores structurally consist of an eclectic mix of curved fullerene-like sheets may affect the arsenic adsorption dynamics within the AC pores and is further complicated by the presence of nano-sized iron-based elements. We have therefore, attempted to shed light on the adsorptive interactions of arsenate-iron nanoparticles with curved fullerene-like sheets by using hybridized quantum mechanics/molecular mechanics (QMMM) calculations and microscopy characterization. It is found that, subsequent to optimization, chemisorption between HAsO42− and the AC carbon sheet (endothermic process) is virtually non-existent – this observation is supported by experimental results. Conversely, the incorporation of iron nanoparticles (FeNPs) into the AC carbon sheet greatly facilitates chemisorption of HAsO42−. Our calculation implies that iron carbide is formed at the junction between the iron and the AC interface and this tightly chemosorbed layer prevents detachment of the FeNPs on the AC surface. Other aspects including electronic structure/properties, carbon arrangement defects and rate of adsorptive interaction, which are determined using the Climbing-Image NEB method, are also discussed. [ABSTRACT FROM AUTHOR]

Rings all of whose right ideals are automorphism-invariant are called right -rings. In the present paper, we study rings having the property that every right cyclic module is dual automorphism-invariant. Such rings are called right -rings. We obtain some of the relationships -rings and -rings. We also prove that; (i) A semiperfect ring is a right -ring if and only if any right ideal in is a left -module, where is a subring of generated by its units, (ii) is semisimple artinian if and only if is semiperfect and the matrix ring is a right -ring for all , (iii) Quasi-Frobenius right -rings are Frobenius. [ABSTRACT FROM AUTHOR]

Worldwide, >18 million persons were infected with fish-borne zoonotic trematodes in 2002. To evaluate the effectiveness of interventions for reducing prevalence and intensity of fish-borne zoonotic trematode infections in juvenile fish, we compared transmission rates at nurseries in the Red River Delta, northern Vietnam. Rates were significantly lower for nurseries that reduced snail populations and trematode egg contamination in ponds than for nurseries that did not. These interventions can be used in the development of programs for sustained control of zoonotic trematodes in farmed fish. [ABSTRACT FROM AUTHOR]