Hung Vuong University

Việt Trì, Vietnam

Hung Vuong University

Việt Trì, Vietnam
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Nguyen Q.N.,University of Gottingen | Nguyen Q.N.,Hung Vuong University | Polle A.,University of Gottingen | Pena R.,University of Gottingen
Trees - Structure and Function | Year: 2017

Key message: European beech presents intraspecific variations in drought resistance strategies that are mediated by the amount of precipitation in the habitat. Abstract: Climate change predictions forecast extended drought periods, which are expected to pose an enhanced risk to forest trees. Here, we investigated the drought response and fitness traits in European beech (Fagus sylvatica L.) in response to a severe progressive drought. The capability of three beech provenances from habitats differing in annual precipitation (544, 665, and 766 mm year−1) to cope with drought was compared in a common garden experiment using beech seedlings. Soil and plant water status, maximum quantum yield of PSII, growth and biomass partitioning, stomatal conductance, and transcript abundance pattern of the kinase, Open Stomata 1 (OST1), of control (well-watered) and drought-treated (water withheld) plants from each provenance were repeatedly measured during a 60-day drought experiment. The lowest precipitation provenance displayed a more isohydric phenotype with a prompt stomatal closure, increased OST1 levels, high water potential and leaf water content, and a decrement in the maximum quantum yield of PSII. The other two provenances showed a more anisohydric stomatal regulation with a slow and delayed stomatal closure and a decrease in the water status. These findings suggest that intraspecific variations in beech for diverging drought resistance strategies exist and might be mediated by differences in the abscisic acid signaling pathway. The higher precipitation provenance maintained high quantum yield of PSII, and water potentials above −2.0 MPa for a longer period of time than the other two provenances, and consequently, mortality was delayed in this provenance. We concluded that lower precipitation adapted plants employ a drought resistance strategy suitable for the moderate drought, whereas the higher precipitation habitat plants revealed mechanisms, which could be better suited to cope with more severe drought events. © 2017, Springer-Verlag Berlin Heidelberg.

Trieu H.-L.,Thai Nguyen University | Nguyen P.-T.,Vietnam National University, Hanoi | Nguyen K.-A.,Hung Vuong University
Advances in Intelligent Systems and Computing | Year: 2014

Sentence alignment plays an extremely important role in machine translation. Most of the hybrid approaches get either a bad recall or low precision. We tackle disadvantages of several novel sentence alignment approaches, which combine length-based and word correspondences. Word clustering is applied in our method in order to improve the quality of the sentence aligner, especially when dealing with the sparse data problem. Our approach overcomes the limits of previous hybrid methods and obtains both highly recall and reasonable precision rates. © Springer International Publishing Switzerland 2014.

Huy N.T.,Hanoi University | Anh N.K.,Hung Vuong University | Thai N.P.,Vietnam National University, Hanoi
Proceedings - 2011 3rd International Conference on Knowledge and Systems Engineering, KSE 2011 | Year: 2011

Functional tags represent the role of syntactic constituents such as noun phrases and verb phrases in a tree. Functional-tag labeling has been studied for languages such as English and Chinese. In this paper, we present a new system for tagging Vietnamese sentences functionally. We used maximum entropy model for this task with six tree-based features. Besides, a new feature based on word cluster has also been made use of. Our experiments on Vietnamese tree bank showed that the system achieved a good performance and the word cluster feature brought a significant improvement. © 2011 IEEE.

Giang P.T.K.,Hung Vuong University | Thu D.X.,Hanoi National University of Education | Quy H.V.,Hanoi National University of Education
Asian Journal of Chemistry | Year: 2013

Arsenic and heavy metals present in wastewater were determined before and after treatment on the adsorbent column is significant science in Vietnam. In this study, we used the available natural materials, it is powdered and Fe(0) yellow sand, MnO2 powder under the granules used as adsorbent in the column. The survey materials were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM). These study showed that the material consists of magnetite Fe3O4 38.18 %, hematite Fe2O 3 12.73 %, wuestite FeO 16.36 % of the beneficial minerals for the adsorption of heavy metals. The results showed that the material can remove As and some heavy metals out of the environment, in particular: arsenic adsorption capacity (169.65 mg/kg) and some metals such as Mn, Fe, Cu, Pb, Cd, respectively: 6616.05, 6664.24, 426.07, 143.06 and 120.21 mg/kg and maintained for a period of 4 days. This shows good potential applications of sand and iron powder Fe(0) in the treatment of heavy metal pollution by column adsorption method.

Dai T.X.,Hanoi University of Science | Con T.H.,Hanoi University of Science | Giang P.H.,Hanoi University of Science | Viet C.,Hung Vuong University
Asian Journal of Chemistry | Year: 2015

Fresh manganese dioxide material was prepared by soaking of pyrolusite grains in HCl solution to dissolve Fe(III) and Mn(II) ions to solution, then MnO2 and FeOOH were relied on oxidation and precipitation reactions to be coating back on the pyrolusite grains surface. The material was used for investigation of methylene blue oxidation process in water solution. In room temperature and at ambient pressure methylene blue was oxidized and decolourized in large range of pH value. The results showed that in acidic solution the manganese dioxide directly oxidize methylene blue and reduced itself into Mn(II) cation. In alkaline solution, manganese dioxide plays the role as an oxidation catalyst to oxidize methylene blue in presence of OH- ions and atmospheric oxygen. The mechanism of oxidation processes was also described. © 2015, Chemical Publishing Co. All rights reserved.

Vc N.-S.,Duy Tan University | Nguyen M.-H.,Hung Vuong University | Nguyen T.-D.,Vietnam Aviation Academy
2013 International Conference on Computing, Management and Telecommunications, ComManTel 2013 | Year: 2013

Replication strategy has been considered as a promising technique for improving data accessibility as well as reducing gateway overload in wireless mesh networks (WMNs). In this regard, popular data is stored in some indicated mesh routers within the network being closer to the users. However, in video streaming applications over WMNs, due to the large size of the videos, it is very challenging for replication strategies to achieve a high quality of experience (QoE) while consuming a minimum storage capacity requirement (SCR). In this paper, as a solution, we propose a novel replication strategy to overcome such challenge by determining an optimal replication density for each segment of a video streaming. The optimal result is based on exploiting not only the skewed access probabilities of video segments as conventional replication strategies but also the skewed encoding rate-distortion information and the loss probability of each frame of a segment. We carefully study the optimization problem in two forms. In the original problem form, our method consumes a minimum SCR under a given constraint of quality playback. In the duality problem form, the proposed scheme provides highest quality playback for a given SCR constraint. Simulation results show that our proposed approach gains a better performance in terms of QoE improvement and SCR saving compared to other existing replication strategies. © 2013 IEEE.

Vo N.-S.,Duy Tan University | Nguyen M.-H.,Hung Vuong University | Ha D.-B.,Duy Tan University | Huynh D.-T.,Ho Chi Minh City University of Transport
2013 International Conference on Computing, Management and Telecommunications, ComManTel 2013 | Year: 2013

In this paper, we propose a joint method of distortion aware opportunistic routing and transmission rate assignment to specifically support video streaming in wireless mesh networks (WMNs). Particularly, we introduce a reduction in reconstructed distortion slope (RDS) metric used for routing algorithm. Based on this metric, each node knows that which is the best successor in the forwarding set by assigning the best transmission rate. As a result, the best path between the sender and the receiver is found to maximize the end-to-end reduction in reconstructed distortion (RRD) for high quality playback. Simulation results are shown to demonstrate that the proposed method significantly improves the quality playback of received video streaming. © 2013 IEEE.

Ngo T.L.,University of Gottingen | Ngo T.L.,Hung Vuong University | Holscher D.,University of Gottingen
Tropical Conservation Science | Year: 2014

Rare tropical tree species are endangered due to the disappearance of old-growth forests. Although some undisturbed oldgrowth and formerly logged forests are protected today, the extent to which rare tree species persist and regenerate in such logged forests is often unclear. In a forested area over limestone in northern Vietnam, we studied the fate of five rare tree species after decades of logging and subsequent nine years of full protection, in comparison with an un-logged forest. Three of the studied species are largely restricted to limestone hills (Excentrodendron tonkinense, Chukrasia tabularis and Garcinia fagraeoides), while two of the species have a wider distribution (Parashorea chinensis and Melientha suavis). The bigger trees of the study species had lower densities and/or differences in the diameter distributions between the two forest types, indicating that these species had formerly been cut. The regeneration stem density of the study species was much lower (46% in M. suavis to 80% in P. chinensis) in the logged than un-logged forest. In the un-logged forest, we found clear relationships between ecological factors and regeneration density in four of the five study species; e.g., the regeneration of E. tonkinense increased with increasing rock-outcrop cover (r = 0.6, p < 0.01). Such relationships were almost absent in the logged forest. The widely distributed generalist species Cleidion javanicum dominated in the tree regeneration of the logged forest. Our results suggest that the studied rare tree species still existed as adults after logging and there was regeneration but at low densities. We assume that the potential for recovery remains, which further justifies the full protection of this and other restoration areas. © The Long Ngo and Dirk Hölscher.

Thi Ai Thu N.,Transport College | Mong Giao N.,Hung Vuong University
Journal of Physics: Conference Series | Year: 2013

The calculation of neutron multiplicity and its energy spectra in (p,n) reactions are very important and necessary for designing and manufacturing the target for an Accelerator Driven System (ADS). The neutron multiplicity in (p,n) reactions on different thin targets with different proton beam energies has been presented in the JENDL-HE library. However, the target used in the ADS must be thick so that the number of neutrons produced is as large as possible. For this reason, we can't directly use the results in the JENDL-HE library. In this paper, we calculate neutron emission spectra and multiplicity in (p,n) reactions for some thick target nuclei including Pb204, Pb206, Pb207, Pb208, W180, W182 W 184 W186, U235, U238, Au 197 with proton beam energies ranging from 0.5 GeV to 3.0 GeV.

PubMed | Hung Vuong University, Genetics & Biotechnology Team and CNRS Plant Research Laboratory
Type: | Journal: Physiologia plantarum | Year: 2016

Annotation of the Eucalyptus grandis genome showed a large amplification of the dehydration-responsive element binding 1/C-repeat binding factor (DREB1/CBF) group without recent DREB2 gene duplication compared with other plant species. The present annotation of the CBF and DREB2 genes from a draft of the Eucalyptus gunnii genome sequence reveals at least one additional CBF copy in the E. gunnii genome compared with E. grandis, suggesting that this group is still evolving, unlike the DREB2 group. This study aims to investigate the redundancy/neo- or sub-functionalization of the duplicates and the relative involvement of the two groups in abiotic stress responses in both E. grandis and E. gunnii (lower growth but higher cold resistance). A comprehensive transcriptional analysis using high-throughput quantitative real-time polymerase chain reaction (qRT-PCR) was performed on leaves, stems and roots from the two Eucalyptus species after cold, heat or drought treatment. A large CBF cluster accounted for most of the cold response in all the organs, whereas heat and drought responses mainly involved a small CBF cluster and the DREB2 genes. In addition, CBF putative target genes, known to be involved in plant tolerance and development, were found to be cold-regulated. The higher transcript amounts of both the CBF and target genes in the cold tolerant E. gunnii contrasted with the higher CBF induction rates in the fast growing E. grandis. Altogether, the present results, in agreement with previous data about Eucalyptus transgenic lines over-expressing CBF, suggest that these factors, which promote both stress protection and growth limitation, participate in the trade-off between growth and resistance in this woody species.

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