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The efforts of this study aimed to evaluate the feasibility of the nanotubular halloysites in weathered pegmatites (NaHWP) for removing heavy metals (i.e., Cd2+, Pb2+) from water. Furthermore, two novel intelligent models, such as teaching-learning-based optimization (TLBO)-artificial neural network (ANN), and TLBO-support vector regression (SVR), named as TLBO-ANN and TLBO-SVR models, respectively, were proposed to predict the Cd2+ and Pb2+ absorption efficiencies from water using the NaHWP absorbent. Databases used, including 53 experiments for Pb2+ absorption and 56 experiments for Cd2+ absorption from water, under the catalysis of different conditions, such as initial concentration of Pb2+ and Cd2+, solution pH, adsorbent weight, and contact time. Subsequently, the TLBO-ANN and TLBO-SVR models were developed and applied to predict the efficiencies of Cd2+ and Pb2+ absorption from water, aiming to evaluate the role as well as the effects of different conditions on the absorption efficiencies using the NaHWP absorbent. The standalone ANN and SVM models were also taken into consideration and compared with the proposed hybrid models (i.e., TLBO-ANN and TLBO-SVR). The results showed that the NaHWP detected in a Kaolin mine (Vietnam) with 70% nanotubular halloysites is a potential adsorbent for water treatment to eliminate heavy metals from water. The two novel hybrid models proposed, i.e., TLBO-ANN and TLBO-SVR, also yielded the dominant performances and accuracies in predicting the Cd2+ and Pb2+ absorption efficiencies from water, i.e., RMSE = 1.190 and 1.102, R2 = 0.951 and 0.957, VAF = 94.436 and 95.028 for the TLBO-ANN and TLBO-SVR models, respectively, in predicting the Pb2+ absorption efficiency from water; RMSE = 3.084 and 3.442, R2 = 0.971 and 0.965, VAF = 96.499 and 96.415 for the TLBO-ANN and TLBO-SVR models, respectively, in predicting the Cd2+ absorption efficiency from water. Furthermore, the validation results also demonstrated these findings in practice through 23 experiments with the accuracies of 98.3% and 98.37% for the TLBO-ANN and TLBO-SVR models, respectively, in predicting the Pb2+ absorption efficiency from water; the accuracies of 98.3% and 97.46% for the TLBO-ANN and TLBO-SVR models, respectively, in predicting the Cd2+ absorption efficiency from water. Besides, solution pH was evaluated as the most critical parameter that can be adjusted to enhance the performance of the absorption of the heavy metals in this study. By using the NaHWP absorbent and the novel proposed intelligent models developed, heavy metals can be eliminated entirely from water, providing pure water/clean freshwater without any risk of adverse health effects for the short term or long term.

The solar concentrator consisting of prisms is a promising solution for clean energy collection. Concentrator design and allocation plays a key role for efficient solar energy collection. This study investigates a green community with many houses. A solar concentrator is installed on the roof of each house to receive sunlight. Several types of solar concentrators are delivered by a manufacturer who fabricates the solar concentrators to maximize its own profit while maintaining a level of collected energy that is acceptable to the community. A novel dual-objective model is proposed. Given uncertain energy demand, a tradeoff between maximizing the manufacturer's profit and the community's energy collected is achieved when designing and allocating such solar concentrator system. A revised genetic algorithm with chance constrained technique is proposed to seek the best resource portfolio and allocation plan for the solar concentrator system and the corresponding optimal layouts for individual solar concentrators. Pareto frontier analysis for the dual objectives is further given to highlight the proposed compromised solution. Experiments indicate that the proposed method significantly improves both energy collection efficiency and profits earned. The compromised solution is mutually accepted by the two parties. The impact of the variation of demand to profit is examined so that demand information can be quantified. This study contributes simultaneously to resolving the optimal resource portfolio and allocation of solar concentrators at a system level, and to optimizing solar concentrator layout at the individual concentrator level.

Eine Insulinresistenz geht oft mit mitochondrialen Defekten einher. Im Skelettmuskel kann eine mitochondriale Dysfunktion die Insulinempfindlichkeit beeinträchtigen. Interessanterweise scheint der umgekehrte Zusammenhang auch möglich zu sein. Kardiospezifischer Knockout des Insulinrezeptors kann mitochondriale und kontraktile Dysfunktion zur Folge haben. Wir zeigten bereits in einem durch Myokardinfarkt induzierten Herzinsuffizienzmodell, dass kardiale Insulinresistenz und verminderte mitochondriale Genexpression koexistieren. Es bleibt allerdings unklar, welche Veränderung zuerst auftritt und deshalb ursächlich eine Rolle spielen kann. Die vorliegende Arbeit überprüft den Zusammenhang zwischen kardialer Insulinresistenz und mitochondrialer Dysfunktion in einem weiteren etablierten Herzinsuffizienzmodell. Im Unterschied zur vorangegangenen Studie wurde hinsichtlich der obigen Fragestellung der Fokus auf die Chronologie der Veränderungen in der Entwicklung der Herzinsuffizienz gelegt.

Computerized Adaptive Testing - CAT is a form of assessment test which requires fewer test questions to arrive at precise measurements of examinees' ability. One of the core technical components in building a CAT is mathematical algorithms which estimate examinee's ability and select the most appropriate test questions for those estimates. Those mathematical algorithms serve as a locomotive in operating the system of adaptive multiple-choice questions on computers. Our research aims to develop essential mathematical algorithms to a computerised system of adaptive multiple-choice tests. We also build a question bank of 500 multiple-choice questions standardised by IRT theory with the difficulty level follows the normal distribution satisfying Kolmogorov-Smirnov test, to measure the mathematical ability of students in grade 10. The initial outcome of our experiment of the question bank shows: the question bank satisfies the requirements from a psychometric model and the constructed mathematical algorithms meets the criteria to apply in computerised adaptive testing.

In this work, we derive analytical expression for the dispersion coefficient of 85Rb atom for a weak probe laser beam induced by a strong coupling laser beams. Our results show possible ways to control dispersion coefficient by frequency detuning and of the coupling lasers. The results show that a Y-configuration appears two transparent window of the dispersion coefficient for the probe laser beam. The depth and width or position of these windows can be altered by changing the intensity or frequency detuning of the coupling laser fields. Keywords: Electromagnetically induced transparency, dispersion coefficient.

ZnO nanoplates with hexagonal wurtzite structure were synthesized by hydrothermal treatment. The average dimension and average thickness of the plates were $$\sim $$ 200 $$\times $$ 400 and 40 nm, respectively. ZnO nanoplates were deposited on Pt-interdigitated electrodes for the fabrication of gas-sensing devices. The ethanol-sensing properties of the devices were investigated in the dark vs. ultraviolet (UV) illumination. Under the UV illumination, the optimal operating temperature of the devices can be reduced from 237 to $$164{^{\circ }}\hbox {C}$$ and the response of the device was increased from 2.8 to 8.5 towards 1500 ppm ethanol vapour.

In this paper, based on techniques of Malliavin calculus, we obtain an explicit bound for tail probabilities of a general class of additive functionals. Applications to fractional Brownian motion and Cox–Ingersoll–Ross process are given to illustrate the theory.

In this paper we consider a generalized Ait-Sahalia interest rate model. We first extend the space of admissible parameters that ensures the existence of a unique positive solution to the model. Then, we provide an explicit estimate for tail probabilities of solutions.

Tóm tắt: Nghiên cứu này phân tích tình hình sản xuất lúa cánh đồng mẫu lớn (CĐML), mức độ và điều kiện để duy trì mô hình sản xuất lúa CĐML. Một cuộc khảo sát nông hộ được thực hiện tại 3 xã có diện tích lúa lớn ở huyện Lệ Thủy bằng bảng hỏi bán cấu trúc để thu thập thông tin về diện tích, năng suất, sản lượng tiêu thụ, điều kiện sản xuất và khả năng duy trì mô hình sản xuất lúa CĐML. Kết quả cho thấy mô hình sản xuất lúa CĐML đã hình thành các vùng sản xuất lúa tập trung, góp phần giảm số thửa từ 5,7 thửa xuống còn 2,4 thửa/hộ. Diện tích trung bình một CĐML là 76,7 ha với khoảng 212 hộ tham gia sản xuất các giống mới chất lượng cao hơn, giảm được lượng giống sử dụng trung bình từ 5,9 kg/sào xuống còn 4,2 kg/sào, nâng cao năng suất 0,15 tạ/sào, đồng thời giảm được 4,1% tổng chi phí sản xuất so với sản xuất ngoài CĐML. Tuy vậy, mức độ duy trì quy trình sản xuất lúa CĐML còn thấp. Sau 4 năm thực hiện, có đến hơn 81,7% số hộ khảo sát không tiếp tục thực hiện đầy đủ các khâu của quy trình sản xuất lúa CĐML. Trong đó, khâu cùng thu hoạch vào một thời điểm, chăm sóc theo một quy trình và sử dụng đồng loạt một loại giống có tỷ lệ hộ không duy trì thực hiện cao nhất lần lượt là 69,5%, 61,1% và 47,2% số hộ khảo sát. Liên kết tiêu thụ lúa CĐML thông qua hợp đồng với doanh nghiệp còn nhiều hạn chế. Sản lượng lúa CĐML tiêu thụ theo hợp đồng đã giảm từ 40% xuống chỉ còn 15,9% sau 4 năm thực hiện mô hình sản xuất lúa CĐML.Từ khóa: tình hình sản xuất, khả năng duy trì, sản xuất lúa, cánh đồng mẫu lớn

In this note, we investigate the continuity in law with respect to the Hurst index of the exponential functional of the fractional Brownian motion. Based on the techniques of Malliavin's calculus, we provide an explicit bound on the Kolmogorov distance between two functionals with different Hurst indexes., Comment: To appear in Comptes Rendus Mathematique, 7 pages

In the world, university autonomy is considered the advanced governance method targeting improving the quality of higher education. In Vietnam, university autonomy, in particular, financing among public universities, has been experiencing the positive outcomes in line with both world trends and general guidelines of Vietnam’s Communist Party. As one of two National universities in Vietnam, Vietnam National University – Ho Chi Minh has been given a high level of autonomy in terms of training, research, financing, international relations, organization, and personnel since it was founded. Its current effectiveness has, however, witnessed negative results in the autonomous aspect, particularly financing. This paper examines the current situation to point out weaknesses and the cause of such weaknesses in financial autonomy effectiveness of Vietnam National University – Ho Chi Minh; this paper also offers some policy implications including (i) reforming the legal framework towards university autonomy, namely financial autonomy among public tertiary education; (ii) financing allocation reform from the state budget; (iii) improved financial autonomy mechanism at Vietnam National University – Ho Chi Minh; (iv) re-organizing the apparatus and improving personnel quality at Vietnam National University – Ho Chi Minh; (v) strengthening monitoring and internal control.

This research was conducted at Xuan Son National Park, the data was collected on 03 permanent plots, the area of each permanent plot is 1 ha. The data collection has been conducted in the period from 2012 to 2018. The trees are classified into diameter categories of 5 cm starting from 10 cm. The structural simulation model consists of two groups of system elements including: state elements (number of trees categorized by diameter size), intermediate elements (tree density, entering and outgoing tree number of diameter categories, number of died trees of different diameter categories, number of regenerating trees). The processes of forest dynamics (regeneration of trees, change of tree number and natural death of diameter categories) were simulated through an simulation scheme in MM&S Software. The interaction is defined through regression equations: Correlation between the number of regenerating trees and the number of existing trees (R-N0), correlation between the number of diameter-category-changing trees and the number of trees at particular diameter category (Ok-Nk), correlation between the number of died trees and the number of trees at particular diameter category (Mk-Nk). The suitable regression equations (that are selected based on the results of statistic analysis) were input into the model in the simulation diagram in MM&S Software. The model in the simulation diagram has been ran, the graph was created from the results of model running to show the tendencies of the change of the tree diameter categories in time and to see the correlation between the changes of the tree diameter categories of the system. The model was exported from the simulation diagram into text file for illustration.

Dihydroartemisinin was converted to its corresponding alkyne-functionalized esters, which were subsequently deployed as substrates for a 'click' chemistry-mediated coupling-with 3'-azido-3'-deoxythydimine (AZT) to furnish novel triazole-artesunate-AZT hybrid compounds. Moreover, various substituted triazole-artemisinin :hybrids were synthesized based on 'click' chemistry between propargyl-substituted derivatives and artemisinin containing a 2-hydroxypropane unit. Fourteen new hybrids were thus successfully prepared and evaluated as cytotoxic agents, revealing an interesting anticancer activity of four triazole-artemisinin derivative hybrids in KB and HepG2 cancer cell lines.

Stem diameter at breast height (D1.3m) and tree height (H) are commonly used measures of tree growth. Based on correlation analysis between biomass of stem, branches and leaves and stem diameter and height of tree we can identify allometric equation for predicting biomass and carbon sequestration of the vegetation. This study was carried out in the natural forests of Me Linh Station for biodiversity to develop allometric equation between biomass and diameter at breast height and height of tree. The study results indicated that twenty tree species dominate in natural forests in Me Linh Station for Biodiversity and they were selected for sampling. Through the 80 established linear equation models for above and below –ground biomass (AGB and BGB), we found that the biomass of tree species in Me Linh Station for Biodiversity were closely correlated with the diameter factor (R>0.902) and not clearly correlated with the height (correlation coefficient = 0.5498, R2< 0.549). Four regression equations were established, including: Pstem = 25.3051*(D1.3m)0.4627 (R2 : 9.661); Pbranch = 12.1043*(D1.3m)0.5416 (R2 : 9.8); Pleaves = 9.446*(D1.3m)0.5976 (R2 : 0.9363); P total biomass of forest = 25.882*D1.725 with R2: 0.8561) for estimating biomass and carbon sequestration of natural forest at the research site. Đường kính ngang ngực (D1.3m) và chiều cao (H) cây là hai nhân tố thường được dùng để đánh giá sự phát triển của cây gỗ. Việc xây dựng các phương trình tương quan giữa sinh khối (SK) thân, cành, lá, sinh khối tầng cây gỗ, sinh khối của quần xã thực vật với đường kính và chiều cao cây góp phần rất lớn trong dự báo sinh khối và khả năng hấp thụ khí carbon của thảm thực vật. Kết quả nghiên cứu cho thấy 20 loài cây gỗ chiếm ưu thế trong rừng tự nhiên và chúng được chọn để thu mẫu. Mối tương quan giữa sinh khối với 2 nhân tố điều tra rừng là đường kính ngang ngực và chiều cao cây đã đươc kiểm tra thông qua 80 phương trình tương quan. Nhìn chung, sinh khối có tương quan chặt chẽ với nhân tố đường kính (hệ số tương quan R > 0,902), và không tương quan rõ với nhân tố chiều cao (R < 0,5498). Bốn phương trình tính sinh khối cho thảm rừng tại khu vực nghiên cứu đã được thiết lập: SKthân = 25,3051*(D1,3m)0,4627 (R2: 9,661); SKcành: 12,1043*(D1,3m)0,5416 (R2: 9,8); SKlá: 9,446*(D1,3m)0,5976 (R2: 0,9363) và SKtổng = 25,882*D1,725 with R2: 0,8561)., Journal of Vietnamese Environment, Vol 9 No 5 (2018)

This paper has reviewed the recent trends in the trading relations between Vietnam and RCEP countries after a decade of integrating with the regional economies and analyzed the impacts on Vietnam’s exports of tariff reductions in RCEP trading partners. Our analysis has showed that exports to regional markets have substantially increased, and the growth of exports has been accompanied with significant shifts in the composition of exports toward manufacturing products. Tariff reductions under regional FTAs have produced positive effects on Vietnam’s major exports, including agricultural products and electronics products. The increasing complementarity between Vietnam and RCEP partners implies a greater potential for expanding trade in coming years. The formation of a region-wide market under the RCEP can significantly open regional markets for Vietnam’s exports through deeper tariff liberalization, the removal of non-tariff barriers, and the consolidation of the rules of origin.

In this article, we consider a general class of linear advanced differential equations, and obtain explicitly sufficient conditions of convergence and exponential convergence to zero. A necessary condition is provided as well.

We investigate the multivariate central limit theorem for nonlinear statistics by means of Stein's method and Slepian's smart path interpolation method. Based on certain difference operators in theory of concentration inequalities, we obtain two explicit bounds for the rate of convergence. Applications to Rademacher functionals, the runs and quadratic forms are provided as well., Comment: To appear in Acta Mathematica Hungarica, 23 pages

Solar energy is critical for the power needs. The pipe design of parabolic trough in solar energy application systems is critical in the collection of solar energy. Pipes with micro-grooves etched in the inner wall have been widely utilized not only as cooling systems but also as absorber receivers in parabolic troughs for solar thermal absorbers because microgrooves improve heat transfer between the inside and outside walls of the pipe. Liquid is automatically pumped vertically along the microgrooves on the inner pipe wall by capillary force, thus resulting in increased surface heat exchange. This study aims to determine the optimum design for parabolic troughs in solar energy application systems. In line with this, a capillary-driven two-phase flow model was constructed to investigate the liquid behavior in grooved pipes and to maximize heat transfer in the pipes. Specifically, this study examined the influence of different microgrooves, fluids, temperatures, radii, and widths of grooves to analyze the maximum liquid front position in the inner wall pipe and to optimize the pipe design via genetic algorithm. Results show that the proposed genetic algorithm can solve more accurately the heat exchange problem and provide an optimal solution which has larger wetting front compared with previous research.

Quang An, Thua Thien Hue province, Vietnam, is one of the areas with great heavy-mineral potential. The heavy-mineral ore body distributes along the beach with the width of 300–800 m and the length of about 6,100 m. A total of 4,398 samples were collected vertically in a grid pattern from 585 bore holes covering an area of 2.882 km2. The results indicate that the ore body is in marine-eolian sediments at Late Holocene (\( {\text{mvQ}}_{ 2}^{ 2- 3} \)). Useful heavy minerals were ilmenite, rutile, leucoxene, anatase, zircon and monazite which could be found in the intrusive and other rocks in the region. The total heavy minerals (THM) content in the bulk samples is not so high with average of 1.172%. The heavy mineral grains are small with the size of 0.05–0.25 mm and they are well liberated, rounded to sub-rounded. The average thickness of ore body is about 8.3 m, however, its variation is relatively stable with the coefficient of 39.28%. The average content of TiO2 in ilmenites of 58.02% and ZiO2 in zircons of 60.89% indicate that titanium-zirconium heavy minerals in Quang An area have relatively good quality. The proven reserves of total heavy minerals in study area were determined reliably with about 406.595 thousand tons, of which the measured mineral reserve is 68.177 thousand tons and the indicated mineral reserve is 338.418 thousand tons. This paper deals with the distribution and potential of heavy minerals in the study area in order to promote efficient mineral exploitation and mineral processing.

The magnitude of secondary compression is expressed by the secondary compression index, Cα = Δe/Δlog t, in which e = void ratio and t = time. Analysis of test data pertaining to soils of widely varying plasticity characteristics and geological origin indicates that there is an excellent correlation between the initial porosity, no and secondary compression index. In this paper, a simple equation has been suggested between Cα/no and Cα to obtain the secondary compression index of a soil, thereby it helps to eliminate the “time consuming laboratory tests” to find the Cα.